Plugin icon overlaping description

[jfbourdon]

For some plugins, the icon is shown overlaping its description on the browsing page. The Aerodrome Utilities is an example. I guess it is linked to the tall and narrow icon 3:8 format. I don't know if there already is some requirements for plugin icon, but if not, it might be a good idea to force a 1:1 format like 256x256.