Online Photo Editor FreeOnlinePhotoeditor.com
Pixlr is a free online editor of a high calibre. Click the first link (name) to get directly to the online editor or click below to go to the Pixlr site and start the correct version from there.
Online Drawing Program for UI Prototyping Draw.io
Online Prototyping, Collaboration and Workflow Platform InVision
Other Tools:
Photo Collage Online Tool Collage
Federico's Reader 