I can't remove photos from gallery that all have Picasso logo

[AC Question]

I tried deleting but I keep getting unsupported file

 

[ManiacJoe]

Which phone?
Which version of android?
Which carrier?

Which app are you trying to use to do the deletion?
If the "gallery" app will not display the image, it probably will not let you do anything with the image.
Try doing the delete using a file browser app.