AutoCrop does for work for some/most images

[dec]

ok. after doing more testing, Autocrop IS working for some images, but NOT for others (the ones i want to do of course). it was only after i started testing different images in other Folders that i saw that it was working fine for them; so now the question is why not for any of the ones i want?

they are very simple transparent images, but they simply will not crop (unless i do manually of course).

attached are three examples of the images that will NOT crop.
Oh, and the last settings i used - i turned off everything else, eg Canvas Resize etc.

so what is different about them?

[xnview]

you have not an uniform color background