The Server Cannot Process the Image: What WordPress Is Telling You

When WordPress says the server cannot process the image, the upload almost always worked. What failed is the resizing that follows, which unpacks every pixel of the photo into memory before making up to seven smaller copies. We measured that at about a quarter of a gigabyte for a 48 megapixel phone photo. Since WordPress 7.1 the block editor can do the resizing in your browser instead, while the Media Library still does it on the server, so the same photo can fail in one and work in the other. The fix depends on which limit stopped the resize, and your error log usually says which.