Claude downscales images that exceed ~1568px on any edge before processing them. If an image gets downscaled internally, Claude's coordinate estimates become inaccurate. To get reliable coordinates, pre-scale images to fit one of these sizes (the maximum that won't trigger internal resizing):
| Aspect ratio | Image size |
|---|---|
| 1:1 | 1092x1092 px |
| 4:3 | 1268x951 px |
| 3:2 | 1344x896 px |
| 16:9 | 1456x819 px |
| 2:1 | 1568x784 px |
Only horizontal (landscape) or square aspect ratios work for accurate coordinates. Vertical images get internally mapped to one of the horizontal tile layouts above, so the image is processed at a different effective resolution than its actual pixel dimensions. This mismatch makes coordinate estimates inaccurate.
- Pick a horizontal or square size from the table above
- Scale the image to fit within that size (preserving aspect ratio)
- Pad with black to fill the exact dimensions
- Tell Claude the image dimensions so it can estimate coordinates
Token cost formula: tokens = (width × height) / 750
A 1092x1092 image uses ~1590 tokens. Smaller images (e.g. 800x800) use fewer tokens with similar accuracy.
Image size # of Tokens Cost / image Cost / 1k images 200x200 px(0.04 megapixels) ~54 ~$0.00016 ~$0.16 1000x1000 px(1 megapixel) ~1334 ~$0.004 ~$4.00 1092x1092 px(1.19 megapixels) ~1590 ~$0.0048 ~$4.80