Replacing cover pictures in the database

I try to provide every book entered in my Book Connect database with a good cover picture. The cover pictures that are supplied from the core are often of lower quality. I usually find a good replacement online or I upload it from internet or by scanning the book cover.Of course I first delete the original cover picture provided by the core. But in some cases I cannot delete them. While I try to upload the picture of my choice, the old cover keeps coming back. An example is IBAN 9789020434231 (Sietske Altink, Houses of illusions). Is there a solution for that?

If you upload a cover on Book Connect for a book in the Edit Book screen, and it doesn’t save, it could mean that there’s something wrong with the image you’re uploading. This actually only shows when you save and close the Edit screen (it might look like the upload succeeded).

Could you try a different image for that same book, to see if it sticks? And if it does, try opening the original image you were uploading in an image editor, and re-save it.

If it still doesn’t work, can you send me the image? You can upload it here and I can try it.
Or at least let me know what the image format is, and the filesize?