Claude does not process pixels, it processes patches. Each patch is a 28x28-pixel block and counts as one visual token, so an image costs ceil(width / 28) multiplied by ceil(height / 28) tokens. Sending a 3,000 px photo to a model whose standard native long edge is 1,568 px means paying to upload detail that gets downscaled away before the first patch is counted. The high-resolution tier on Claude 4.7 and later raises the ceiling to a 2,576 px long edge and 4,784 visual tokens, but that is still far below a modern camera original. There are two hard rules on top. Each image is limited to 8000x8000 px and 10 MB base64 on the Claude API, 5 MB on Amazon Bedrock. And once a single request carries more than 20 images, a stricter per-image dimension limit applies to every image in that request unless you resize so neither dimension exceeds 3,000 px. Supported formats are JPEG, PNG, GIF and WebP, with animations unsupported and only the first frame used, and Claude does not read metadata at all. Skwish resizes to the exact long edge you need, converts format and compresses in the browser, batched into one ZIP.