Adobe has opened the registrations to their really phat looking online photo editing tool “Adobe Photoshop Exress“. Its based on Flash and runs fine on Safari. On Firefox i had some problems.
The editing features are not comparable to the real Photoshop Software or maybe GIMP, but for quick modifying of pictures its sufficient, i think.
But watch out what kind of photos you upload, because you grant Adobe a very exclusive right (see https://www.photoshop.com/express/terms.html):
[...] However, with respect to Your Content that you submit or make available for inclusion on publicly accessible areas of the Services, you grant Adobe a worldwide, royalty-free, nonexclusive, perpetual, irrevocable, and fully sublicensable license to use, distribute, derive revenue or other remuneration from, reproduce, modify, adapt, publish, translate, publicly perform and publicly display such Content (in whole or in part) and to incorporate such Content into other Materials or works in any format or medium now known or later developed.