Looked like a good app. Setting the alt-Text works fine, renaming and resizing the files, too!
But I reverted the resizing, because I wasn't satisfied with the results, the images stayed the same size. Now I have low quality product images in my shop...even they said reverting is possible for 3 months
After spending $10 to have pictures resized I was very displeased with the quality ( pictures were pretty much all grainy). Looks like I will be spending more money to have them reverted back to original... 600px did not work very well.