I need help importing a image file

I am trying to import a png with a transparent background off google into adobe animate. When I press import to library,  a error pops up saying that "One or more files were not imported because there were problems reading them." This error has come before, when I tried to upload a audio file and didn't know it had to be 16-bit in order for Animate to read it. Does anyone know how to fix this, and make sure that the file is readable? I don't have Photoshop, and I hope that fact doesn't make it harder.