ITHMB is legacy and read-only here
ITHMB is an older raster format. It can usually be opened and converted from, but it's long obsolete, so there's no modern encoder to create new ITHMB files.
Looking to convert HEIC to ITHMB? Here's the honest answer — and what works instead.
Turn your file into a share-worthy AI Effect — one tap, no prompts.
HEIC is the high-efficiency format iPhones and iPads use to store photos — about half the size of JPG, but not supported everywhere, so it often needs converting.
HEIC opens on Apple devices and Windows 11; older systems need it converted to JPG/PNG.
Not here — ITHMB is a legacy format with no modern encoder. We can often read ITHMB as a source, but for output use a current format like PNG, JPG or TIFF.
HEIC converts to PNG, JPG or TIFF — free, no sign-up, no watermark.