Important note when using images: be sure to check in advance the type of licence attached to each image you plan to use for your communication. Be aware that the image status migh differ according to the nature of the organisation you work for/represent!
IMAGE SOURCES
CCSearch a creative-common resource for images (free, conditions apply. Please check the credit rules for the images you plan to use)
IMAGE EDITING
Muro Deviant Art advance online image editing (free)
SumoPaint advance online image editing (free)
Pixlr advance online image editing (free)
IMAGE SHARING
Flickr image sharing (freemium)
Instagram advance online image editing (free)