These are 3 very useful bookmarks for all PJ members. The first two were written by Hatch. The third was created by 1ucas. All 3 are must haves.
PJ Challenge Checker- PJ Spec Checker - GIF Animation Viewer
PJ Challenge Checker:
Use this utility to verify and check your entry to any weekly challenge. Simply paste a link to the entry and choose the challenge.
PJ Spec Checker
This useful utility will check your colors.
GIF Animation Viewer
A little web tool for analyzing GIF animations frame by frame. Just submit the GIF URLs and you'll get a handy toolbar under each GIF file. All images on the viewer page are also zoomable, just click over them to zoom in, shift or ctrl click to zoom out and alt+click for resetting the zoom.
There's a couple of bookmarklets in there too, for submitting whichever page you are to the viewer or just embedding the toolbar code on any website you visit. New features coming soon!