Advances in image generation have made synthetic images increasingly difficult to distinguish from real photographs, raising concerns about the trustworthiness of visual media. Existing AI-generated image detectors often perform well on in-domain data, but their robustness and cross-generator generalization remain limited. These limitations are commonly attributed to overfitting to shortcut cues. Although many methods seek to suppress shortcut learning, most retain binary classification as the training task without reconsidering how the task itself shapes the learned representations. We introduce CuRe, a framework for learning Continuous Source Responses that revisits authenticity detection from the perspective of the training task. CuRe reformulates backbone adaptation as regression of real-generated mixing ratios, providing finer supervision that encourages the model to capture authenticity-related variation beyond binary endpoint separation. We further select a compact source-response subspace to suppress nuisance variation and limit the final classifier's access to potential shortcut cues. Across ten public benchmarks, CuRe achieves an average balanced accuracy of 89.7%, exceeding the second-best method by 5.2 percentage points. Further experiments demonstrate consistent generalization gains across visual backbones and strong robustness to common image degradations. Code is available at https://github.com/manic-cui/CuRe
Figures & tables
Figure 1: Comparison of binary and continuous source supervision. Left: binary labels provide only coarse endpoint supervision, allowing models to learn decision boundaries based on different shortcuts (dashed curves), potentially compromising robustness and generalization. Right: CuRe constructs continuous transitions from real ( α=0 ) to generated ( α=1 ) images and predicts the mixing ratio α , providing finer-grained supervision that encourages the encoder to distinguish intermediate states and become more sensitive to changes in image authenticity.
Figure 2: Representation analysis using PE Core L/14 on GenImage. Frozen and binary-trained features retain pronounced semantic structure, and binary training additionally separates the two JPEG qualities. In contrast, continuous source-change training yields greater mixing across semantic and format groups while producing clearer separation between real and generated samples.
Figure 3: Overview of the CuRe framework. Stage 1 (left) adapts the backbone with LoRA to predict the mixing ratio of real–generated image interpolations, encouraging sensitivity to continuous source changes. Stage 2 (upper right) uses the frozen adapted encoder and real–generated trajectories to extract a compact subspace that preserves source responses while suppressing content and mixing-related variation.
Standard Benchmarks
In-the-Wild Benchmarks
Method
AIGCDetect
AIGIBench
UnivFD
EvalGEN
SynthWildX
WildRF
BFree-On.
RRDataset
RealChain
Chameleon
Overall Avg.
NPR (CVPR’24) ( Tan et al., 2024 )
63.5
63.9
53.5
86.3
47.4
51.9
46.7
49.3
50.7
54.9
56.8
UnivFD (CVPR’23) ( Ojha et al., 2023 )
67.4
74.7
50.8
94.5
61.6
57.3
64.9
61.2
66.1
62.1
66.1
FatFormer (CVPR’24) ( Liu et al., 2024 )
61.3
63.4
52.6
65.1
52.6
57.7
60.7
50.3
50.0
50.6
56.4
C2P-CLIP (AAAI’25) ( Tan et al., 2025 )
78.4
69.6
91.6
66.4
55.3
59.5
50.0
52.7
50.2
50.7
62.4
DRCT (ICML’24) ( Chen et al., 2024 )
68.3
73.4
56.7
75.4
74.6
73.8
73.8
60.5
64.9
68.5
69.0
Table 1: Overall comparison across AIGI detection benchmarks. All entries are in % and all accuracy values are balanced accuracy. Each benchmark score is the unweighted macro-average over its evaluated subsets when applicable. Best and second-best average results are marked in bold and underlined, respectively.
Subset Subset Subset
NPR NPR NPR
UnivFD UnivFD UnivFD
FatFormer FatFormer FatFormer
C2P-CLIP C2P-CLIP C2P-CLIP
DRCT DRCT DRCT
SAFE SAFE SAFE
DDA DDA DDA
GAPL GAPL GAPL
DGS-Net DGS-Net DGS-Net
CuRe CuRe CuRe
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
GAN-based Noise-to-Image Generation
ProGAN
50.4
50.9
52.7
55.1
58.0
84.7
98.5
99.8
54.5
61.5
51.6
53.1
85.3
98.5
99.7
100.0
94.9
99.0
95.2
99.8
R3GAN
62.5
67.5
71.5
80.5
50.3
78.3
83.6
93.9
49.0
40.7
63.0
54.6
95.8
99.1
96.2
99.8
72.4
85.0
96.1
99.0
StyleGAN3
62.6
77.4
65.0
72.5
78.1
92.8
93.1
98.8
52.2
59.5
53.4
62.2
63.3
77.1
97.0
99.7
61.4
79.0
92.6
97.9
StyleGAN-XL
68.4
72.9
75.9
84.1
64.2
86.7
91.3
97.7
49.0
46.1
64.9
79.9
48.8
43.3
95.3
99.0
53.7
72.6
96.9
99.7
Table 2: Subset-level results on AIGIBench. Each method reports B.Acc./AUC (%). Best and second-best results in the Average row are marked in bold and underlined, respectively.
Figure 4: Cross-backbone comparison under different LoRA ranks on AIGIBench. Within each backbone, paired bars compare binary supervision (blue) and continuous-ratio supervision (teal with diagonal hatching) at r∈{16,32,64} . Bars report ROC-AUC.
Subset Subset Subset
NPR NPR NPR
UnivFD UnivFD UnivFD
FatFormer FatFormer FatFormer
C2P-CLIP C2P-CLIP C2P-CLIP
DRCT DRCT DRCT
SAFE SAFE SAFE
DDA DDA DDA
GAPL GAPL GAPL
DGS-Net DGS-Net DGS-Net
CuRe CuRe CuRe
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
SynthWildX
DALL-E 3
41.1
33.0
63.7
71.8
52.2
65.9
54.9
66.7
85.1
91.8
58.1
57.0
92.4
97.4
87.2
94.3
49.4
51.9
94.6
97.5
Firefly
49.5
46.9
59.0
63.7
52.6
51.8
59.1
78.8
59.3
67.7
53.3
54.8
86.8
93.7
87.4
94.9
51.9
67.2
88.6
94.5
Midjourney v5
51.6
49.0
62.2
70.2
53.2
62.3
51.8
63.4
79.3
88.6
56.5
58.4
92.8
97.9
84.6
92.6
49.5
49.1
94.9
97.7
Average
47.4
43.0
61.6
68.6
52.6
60.0
55.3
69.6
74.6
82.7
56.0
56.7
90.7
96.3
86.4
93.9
50.3
56.1
92.7
96.6
Table 3: Subset-level results on SynthWildX and WildRF. Each method reports B.Acc./AUC (%). SynthWildX pairs each generated subset with the shared real set. Best and second-best results in the Average rows are marked in bold and underlined, respectively.
Table 8
Figure 5: Robustness of CuRe and four strong comparison methods on AIGIBench (BAcc). Each panel varies one post-processing factor while holding the other two at their clean settings.
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
Subset Subset Subset
NPR NPR NPR
UnivFD UnivFD UnivFD
FatFormer FatFormer FatFormer
C2P-CLIP C2P-CLIP C2P-CLIP
DRCT DRCT DRCT
SAFE SAFE SAFE
DDA DDA DDA
GAPL GAPL GAPL
DGS-Net DGS-Net DGS-Net
CuRe CuRe CuRe
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
GAN-based Generation
BigGAN
45.9
45.3
49.5
55.3
50.2
68.6
98.3
99.9
53.4
61.1
50.0
44.9
87.2
94.8
98.0
100.0
88.3
94.7
93.5
99.7
CycleGAN
70.2
84.7
53.0
60.5
55.5
92.9
98.9
100.0
48.1
51.8
55.7
60.9
71.3
84.9
97.3
99.6
96.7
99.3
70.4
98.6
GauGAN
47.0
46.5
52.1
68.5
50.9
84.3
98.6
99.8
50.1
43.6
49.5
43.8
88.8
95.9
99.4
100.0
88.4
94.4
94.2
99.8
ProGAN
50.4
50.9
52.7
55.1
58.0
84.7
98.5
99.8
54.5
61.5
51.6
53.1
85.3
98.5
99.7
100.0
94.9
99.0
95.2
99.8
Appendix
Table 6: Subset-level results on AIGCDetectBenchmark. Each method reports B.Acc./AUC (%). Best and second-best results in the Average row are marked in bold and underlined, respectively.
Subset Subset Subset
NPR NPR NPR
UnivFD UnivFD UnivFD
FatFormer FatFormer FatFormer
C2P-CLIP C2P-CLIP C2P-CLIP
DRCT DRCT DRCT
SAFE SAFE SAFE
DDA DDA DDA
GAPL GAPL GAPL
DGS-Net DGS-Net DGS-Net
CuRe CuRe CuRe
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
B.Acc.
AUC
BigGAN
45.9
45.3
49.5
55.3
50.2
68.6
98.3
99.9
53.4
61.1
50.0
44.9
87.2
94.8
98.0
100.0
88.1
94.5
93.5
99.7
CRN
46.3
23.6
46.7
42.4
49.7
55.9
91.3
98.8
50.3
47.2
51.4
60.5
78.6
89.8
89.8
97.1
61.3
70.1
72.4
84.7
CycleGAN
70.2
84.7
53.0
60.5
55.5
92.9
98.9
100.0
48.1
51.8
55.7
60.9
71.3
84.9
97.3
99.6
96.3
99.1
70.4
98.6
Deepfake
52.6
53.3
54.4
63.8
57.3
75.7
92.6
97.2
59.7
62.6
50.0
48.6
75.2
84.9
85.2
96.4
61.5
76.9
64.5
96.7
GauGAN
47.0
46.5
52.1
68.5
50.9
84.3
98.6
99.8
50.1
43.6
49.5
43.8
88.8
95.9
99.4
100.0
88.5
94.4
94.2
99.8
Appendix
Table 7: Subset-level results on UnivFakeDetect. Each method reports B.Acc./AUC (%). Best and second-best results in the Average row are marked in bold and underlined, respectively.
Backbone
Supervision
r=16
r=32
r=64
CLIP ViT-L/14
Binary
75.42
72.20
74.89
CuRe (Ours)
79.42
79.34
80.13
Δ
+4.00
+7.14
+5.24
DINOv2 ViT-L/14
Binary
74.32
72.52
76.57
CuRe (Ours)
81.21
81.79
83.49
Δ
+6.89
+9.27
+6.92
Appendix
Table 8: Detailed cross-backbone results corresponding to Figure 4 . ROC-AUC scores and their differences are reported in % on AIGIBench. Δ is computed by subtracting the binary supervision score from the CuRe score.
Setting
UnivFD
DRCT
DDA
GAPL
CuRe (Ours)
JPEG compression
q=100
74.70
73.40
85.00
91.30
92.80
q=90
72.19
72.00
82.00
89.14
93.09
q=70
73.22
71.09
77.23
85.78
92.74
q=50
70.64
67.73
74.17
81.87
91.72
q=30
64.78
64.71
70.53
74.68
90.43
Appendix
Table 9: Detailed robustness results corresponding to Figure 5 . Each entry is the 20-subset macro-average B.Acc. (%) on AIGIBench. Only one post-processing factor is varied at a time, while the other factors remain at their clean settings.
Dataset
Real/Fake
Source
#Models
Model types
AIGCDetectBenchmark ( Zhong et al., 2023 )
76.3k/76.3k
LSUN, MSCOCO, ImageNet, CelebA, FFHQ
17
GAN, diffusion
AIGIBench ( Li et al., 2025c )
84.0k/84.0k
Curated sources, social media, AI-art platforms
20
GAN, diffusion, personalized, other
UnivFakeDetect ( Ojha et al., 2023 ; Wang et al., 2020 )
45.2k/45.2k
LSUN, ImageNet, CelebA, and others
13
GAN and other
EvalGEN ( Chen et al., 2025 )
0/55.3k
Prompts
5
Diffusion, autoregressive
SynthWildX ( Cozzolino et al., 2024 )
0.5k/1.5k
X
3
Commercial text-to-image
WildRF ( Cavia et al., 2024 )
1.3k/1.3k
Reddit, Facebook, X
Unknown
Unknown
Appendix
Table 10: Test-set statistics of the ten evaluation benchmarks, including image counts, data sources, and generator coverage. Real/Fake lists the numbers of real and generated images; a combined count is marked as total. Counts above one thousand are expressed in thousands (k), rounded to one decimal place. Shared real-image pools are counted once, and additional real images used only for evaluation pairing are excluded. Unknown indicates that the generator identity or model family is unavailable for in-the-wild images.
AI-generated image detection identifies synthetic or AI-edited images and develops methods that generalize across generators, domains, and image transformations.