I think that's what restart markers are for in JPEG from the original spec. IIRC in JPEG you can have markers that are marked as "crucial for proper decode" and

I think that's what restart markers are for in JPEG from the original spec. IIRC in JPEG you can have markers that are marked as "crucial for proper decode" and programs should reject the image if they don't understand them. Maybe the latter was from PNG I forget.