Thumbnail Error

The following error(s) occurred:

• The image being resized is not a valid jpg, webp, png or gif.

Query String: src=%2Fimages%2Fimmagine_bambini.bmp&w=400&h=200&zc=1
TimThumb version: 2.8.16
Instruction: RAXO thumbnails don't work — what to do? (registration required)