Face-Swap LoRA for FLUX 2 Klein 9B
Prompt face_swap: take the face from Picture 1 and swap it onto the person in Picture 2. the result should show the exact face and features from Picture 1 on the body, pose, and scene from Picture 2, with natural skin tone blending and matching lighting. Prompt face_swap: take the face from Picture 1 and swap it onto the person in Picture 2. the result should show the exact face and features from Picture 1 on the body, pose, and scene from Picture 2, with natural skin tone blending and matching lighting. Prompt face_swap: take the face from Picture 1 and swap it onto the person in Picture 2. the result should show the exact face and features from Picture 1 on the body, pose, and scene from Picture 2, with natural skin tone blending and matching lighting. Prompt face_swap: take the face from Picture 1 and swap it onto the person in Picture 2. the result should show the exact face and features from Picture 1 on the body, pose, and scene from Picture 2, with natural skin tone blending and matching lighting. Prompt face_swap: take the face from Picture 1 and swap it onto the person in Picture 2. the result should show the exact face and features from Picture 1 on the body, pose, and scene from Picture 2, with natural skin tone blending and matching lighting. Prompt face_swap: take the face from Picture 1 and swap it onto the person in Picture 2. the result should show the exact face and features from Picture 1 on the body, pose, and scene from Picture 2, with natural skin tone blending and matching lighting. A LoRA adapter for FLUX 2 Klein 9B fine-tuned for high-quality face swapping. Given a face source image and a body/scene image, the model produces a natural face swap preserving identity, lighting, and skin tone.
Prompt
Use the following prompt for best results:
face_swap: take the face from Picture 1 and swap it onto the person in Picture 2. the result should show the exact face and features from Picture 1 on the body, pose, and scene from Picture 2, with natural skin tone blending and matching lighting.
Picture 1 : Face source image (the identity to transfer)Picture 2 : Body/scene image (the target pose and environment)
How to Use
Try it on fal
Open on fal.ai
Via fal.ai API
import fal_client
def on_queue_update (update ):
if isinstance (update, fal_client.InProgress):
for log in update.logs:
print (log["message" ])
result = fal_client.subscribe(
"fal-ai/flux-2-klein/9b/base/edit/lora" ,
arguments={
"prompt" : "face_swap: take the face from Picture 1 and swap it onto the person in Picture 2. "
"the result should show the exact face and features from Picture 1 on the body, pose, "
"and scene from Picture 2, with natural skin tone blending and matching lighting." ,
"model_name" : None ,
"loras" : [{
"path" : "https://huggingface.co/ilkerzgi/face-swap/resolve/main/FS2_V2_r32_800_pytorch_lora_weights.safetensors" ,
"scale" : 1
}],
"embeddings" : [],
"image_urls" : [
"https://example.com/face_source.png" ,
"https://example.com/body_scene.png"
],
"num_images" : 4
},
with_logs=True ,
on_queue_update=on_queue_update,
)
print (result)
Evaluation Overview
Test Cases
LoRA Variants
Image Models
Total Generations
Dataset Sizes
25 9 3 300 300 / 800
9 LoRA variants were trained with different hyperparameters and evaluated against 3 image models across 25 diverse test subjects.
Training Configurations
Variant
Samples
Rank
Steps
LR
Guidance
Avg Latency
V1 r16 (300)
300
16
3000
5e-5
1
6.0s
V2 r32 (300)
300
32
3500
5e-5
1
6.1s
V3 r32+cfg (300)
300
32
3500
5e-5
3.5
6.6s
V1 r16 (800)
800
16
3000
5e-5
1
6.4s
V2 r32 (800)
800
32
3500
5e-5
1
6.3s
V3 r32+cfg (800)
800
32
3500
5e-5
3.5
6.2s
V4 r32 long (800)
800
32
5000
5e-5
1
6.4s
V5 r64 (800)
800
64
4000
3e-5
1
6.4s
V6 r32 slow (800)
800
32
5000
1e-5
1
6.4s
Image Models
Model
Avg Latency
Nano Banana 2
28.8s
Nano Banana Pro
33.3s
GPT Image 1.5
30.3s
Latency Comparison
Model
Avg Latency
V1 r16 (300)
6.0s
V2 r32 (300)
6.1s
V3 r32+cfg (800)
6.2s
V2 r32 (800)
6.3s
V6 r32 slow (800)
6.4s
V4 r32 long (800)
6.4s
V5 r64 (800)
6.4s
V1 r16 (800)
6.4s
V3 r32+cfg (300)
6.6s
Nano Banana 2
28.8s
GPT Image 1.5
30.3s
Nano Banana Pro
33.3s
All LoRA variants average ~6-7s , while image models average ~29-33s .
Model Weights
Test Cases (25)
#1 — middle-aged woman with short stylish grey hair and blue eyes, elegant bone structure
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
6.7s
8.9s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
7.3s
6.6s
6.6s
6.6s
6.6s
6.6s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
35.3s
39.6s
27.7s
#2 — young woman with long straight brown hair parted in the middle and brown eyes
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
6.6s
6.1s
7.1s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
5.7s
7.1s
6.8s
7.1s
9.4s
6.8s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
24.0s
32.5s
44.6s
#3 — older woman with short white curly hair and warm brown eyes
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
6.1s
6.3s
5.9s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
6.6s
6.6s
6.6s
6.6s
6.6s
6.6s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
25.0s
30.4s
50.6s
#4 — young African American woman with braided hair and warm brown eyes
#4 — young African American woman with braided hair and warm brown eyes
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
7.5s
7.4s
5.8s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
6.6s
6.6s
7.6s
6.6s
5.7s
6.6s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
31.0s
36.6s
28.0s
#5 — young woman with short blonde bob haircut and bright blue eyes, Scandinavian features
#5 — young woman with short blonde bob haircut and bright blue eyes, Scandinavian features
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
5.7s
5.7s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
8.0s
6.6s
6.1s
6.7s
6.9s
5.7s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
26.5s
41.0s
25.3s
#6 — young Hispanic man with wavy dark hair and brown eyes, trimmed goatee
#6 — young Hispanic man with wavy dark hair and brown eyes, trimmed goatee
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
5.7s
5.7s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
6.1s
7.1s
6.1s
6.6s
6.6s
6.6s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
25.4s
42.3s
24.0s
#7 — young South Asian man with dark thick hair and brown eyes, short neat beard
#7 — young South Asian man with dark thick hair and brown eyes, short neat beard
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
6.6s
5.7s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
6.6s
6.6s
6.6s
7.1s
7.5s
7.1s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
23.0s
31.3s
25.4s
#8 — young man with a buzz cut and hazel eyes, tanned skin
#8 — young man with a buzz cut and hazel eyes, tanned skin
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
6.2s
6.6s
6.7s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
6.1s
6.6s
6.6s
6.8s
5.5s
5.7s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
28.5s
39.8s
26.6s
#9 — young Middle Eastern man with dark wavy hair and olive skin, prominent eyebrows
#9 — young Middle Eastern man with dark wavy hair and olive skin, prominent eyebrows
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
5.9s
6.6s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
6.1s
7.3s
8.9s
6.6s
5.7s
6.6s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
25.3s
44.6s
66.6s
#10 — young man with curly black hair and deep brown eyes, clean-shaven
#10 — young man with curly black hair and deep brown eyes, clean-shaven
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
6.4s
5.7s
5.7s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
5.7s
7.1s
6.1s
7.0s
6.7s
6.6s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
43.9s
31.3s
25.2s
#11 — young African American woman with short natural TWA hairstyle and dark brown eyes, high cheekbones
#11 — young African American woman with short natural TWA hairstyle and dark brown eyes, high cheekbones
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
6.7s
6.6s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
9.8s
7.5s
5.7s
6.6s
6.1s
7.5s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
26.1s
23.3s
25.3s
#12 — young woman with tight blonde curls, dark brown skin, bright smile, dimples
#12 — young woman with tight blonde curls, dark brown skin, bright smile, dimples
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
5.4s
10.3s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
5.7s
5.7s
6.1s
6.6s
6.2s
6.6s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
30.6s
25.8s
25.4s
#13 — young woman with tight blonde curls, dark brown skin, bright smile, dimples
#13 — young woman with tight blonde curls, dark brown skin, bright smile, dimples
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
7.1s
5.7s
7.0s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
5.7s
6.6s
5.7s
7.0s
5.8s
6.8s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
24.1s
24.4s
26.6s
#14 — middle-aged woman with dark skin, close-cropped natural hair, elegant gold jewelry
#14 — middle-aged woman with dark skin, close-cropped natural hair, elegant gold jewelry
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
7.1s
7.5s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
7.1s
5.7s
7.1s
5.7s
7.1s
7.1s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
19.4s
24.7s
28.1s
#15 — young Nordic man with platinum blonde hair, ice blue eyes, sharp cheekbones, clean shaven
#15 — young Nordic man with platinum blonde hair, ice blue eyes, sharp cheekbones, clean shaven
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
5.7s
6.6s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
6.6s
5.7s
5.7s
5.7s
7.5s
7.1s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
26.4s
42.2s
25.3s
#16 — middle-aged Hispanic woman with dark wavy hair streaked with grey, warm brown eyes, round face
#16 — middle-aged Hispanic woman with dark wavy hair streaked with grey, warm brown eyes, round face
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
5.7s
10.3s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
5.4s
5.7s
5.7s
7.5s
7.1s
6.6s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
45.2s
34.2s
24.0s
#17 — young Pacific Islander woman with long wavy dark hair, brown eyes, strong features
#17 — young Pacific Islander woman with long wavy dark hair, brown eyes, strong features
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
5.7s
7.1s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
5.7s
8.1s
5.7s
5.7s
5.7s
6.7s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
20.0s
28.0s
27.3s
#18 — older Eastern European man with a thick grey mustache, lined face, piercing grey eyes
#18 — older Eastern European man with a thick grey mustache, lined face, piercing grey eyes
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
5.9s
5.7s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
5.7s
5.7s
5.7s
5.7s
5.7s
5.2s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
20.7s
24.0s
26.7s
#19 — older African American woman with silver locs, deep brown eyes, and laugh lines, regal posture
#19 — older African American woman with silver locs, deep brown eyes, and laugh lines, regal posture
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
6.2s
6.1s
5.7s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
5.7s
5.9s
5.7s
5.7s
5.7s
6.6s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
25.7s
58.2s
24.8s
#20 — older Chinese woman with jet black dyed hair, round face, gentle brown eyes, pearl earrings
#20 — older Chinese woman with jet black dyed hair, round face, gentle brown eyes, pearl earrings
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
6.6s
5.7s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
6.8s
5.7s
5.7s
7.1s
5.6s
5.6s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
35.0s
27.9s
28.3s
#21 — middle-aged woman with fiery red curly hair and freckled pale skin, green eyes, strong jawline
#21 — middle-aged woman with fiery red curly hair and freckled pale skin, green eyes, strong jawline
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.6s
5.7s
5.6s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
5.7s
5.7s
5.7s
5.7s
6.6s
5.7s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
41.1s
36.6s
27.9s
#22 — young Southeast Asian man with black hair, smooth brown skin, sharp jawline
#22 — young Southeast Asian man with black hair, smooth brown skin, sharp jawline
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.7s
5.7s
5.7s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
5.7s
5.7s
6.6s
5.7s
5.7s
5.7s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
25.3s
28.8s
25.3s
#23 — middle-aged woman with natural grey afro, dark skin, reading glasses on nose
#23 — middle-aged woman with natural grey afro, dark skin, reading glasses on nose
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
6.6s
5.7s
5.7s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
6.1s
5.7s
5.8s
5.6s
6.6s
5.7s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
34.1s
22.0s
24.6s
#24 — middle-aged Hispanic woman with dark wavy hair streaked with grey, warm brown eyes, round face
#24 — middle-aged Hispanic woman with dark wavy hair streaked with grey, warm brown eyes, round face
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
5.6s
5.7s
6.1s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
7.8s
5.7s
5.9s
5.7s
5.7s
5.7s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
31.9s
24.7s
26.0s
#25 — older East Asian man with thinning grey hair, wire-rimmed glasses, kind wrinkled eyes
#25 — older East Asian man with thinning grey hair, wire-rimmed glasses, kind wrinkled eyes
Face Source
Body / Scene
Ground Truth
LoRA — 300 Samples
V1 r16 (300)
V2 r32 (300)
V3 r32+cfg (300)
6.6s
5.7s
6.0s
LoRA — 800 Samples
V1 r16 (800)
V2 r32 (800)
V3 r32+cfg (800)
V4 r32 long (800)
V5 r64 (800)
V6 r32 slow (800)
5.7s
5.7s
5.4s
5.7s
5.7s
5.7s
Image Models
Nano Banana 2
Nano Banana Pro
GPT Image 1.5
25.3s
37.3s
46.7s
Training Details
Base Model : FLUX 2 Klein 9B Method : LoRA (Low-Rank Adaptation)Trainer : fal-ai/flux-2-klein-9b-base-trainer Datasets : Two custom face-swap paired datasets (300 and 800 samples)Rank variants tested : 16, 32, 64Training steps : 3,000 – 5,000Learning rates : 1e-5 to 5e-5Guidance scale : 1.0 and 3.5
Author
Ilker Izgi — Creative Engineer at fal
