Fitting. Text size is a percentage of the image width, so the same setting looks the same on a 600-pixel photo and a 4,000-pixel one. Lines are wrapped word by word to the image width (minus a margin); if a caption still needs more than four lines it is shrunk step by step until it fits. Press Enter in a text box to force a line break.

Fonts. Impact ships with Windows and macOS but not with most Android phones or Linux desktops, so the browser falls back to Arial Black or its boldest sans-serif. That is why a meme made on a phone can look slightly different from one made on a laptop. Nothing is downloaded from a font server — that would be a network request, and this tool makes none.

Output. The download is a PNG at the original image resolution (capped at 4,096 pixels on the long side to keep phones from running out of memory). "Copy image" uses the clipboard API where the browser supports it — Safari and Firefox may only offer download. Animated GIFs are flattened to their first frame.

Privacy. The picture is read into an in-page canvas and never uploaded. Close the tab and it is gone. Text you type is not stored either.