Tile Check
Preview a repeating tile and see where its edges meet.
Images are processed in your browser.
Drop a tile here
PNG, JPEG, WebP or another image your browser can open
Left ↔ Right
Top ↔ Bottom
Checks use the original pixels. Join and Interior are the average change between neighboring pixels, from 0 to 255. Edges that differ can still repeat smoothly, so judge the join by eye in the preview.