I tried to edit the thumbnails size from 90x90 to bigger sizes from the store configuration panel, but the thumbnails remain the same size. In the shop>media files component, the thumbnails are in the requested size, but in the front end the thumbnails remains 90x90.
of course, because this is depending from your template.
The thumbnail size is not necesarily the displayed size, it is the auto generated thumbnail size. The thumbnail is then used in different cases and different sizes.
change the css container, and also delete the old thumbnails from the resized folder, before changing the values to larger