ImageOptim icon is ugly. No doubt about it :)
However, despite the uglyness it does have two properties of a good icon: distinct shape and distinct color. The black splattered nobody-knows-what symbol clearly stands out in the sea of shiny silverish-with-hint-of-color tilted-rectangle icons.
I'd love to see a better-looking icon that still stands out (rather than being e.g. some variation of Preview.app's icon).
Also, I may need ability to migrate to the new icon gradually. The old one has been used for so long that's all over the web and people are used to it (call it Stockholm Syndrome if you like ;) I don't want to suddenly auto-update everybody's ImageOptim one day and have them wonder "where's ImageOptim gone!?!" (e.g. I could first make old icon with shade/color of the new one, then use new one, but maybe with darker outline, etc.)
The current crush-warning-sign symbol is obscure, so doesn't need to be kept.
I was thinking about icon with thick black scissors (to keep feel black X that current icon has) trimming away white border from a photo.
Alternative idea is a thick bundle of images squeezed in the middle with measuring tape (that could have KB symbols instead of cm/inch :)