Excellent collection of copyright free and/or creative commons clipart/graphics/images that you can use in your teaching materials online can be found at Shambles.net
The tool below will help you format a feed’s display with the information you want to use on your web site. All you need to enter is the URL for the RSS source, and select the desired options below. Note that we now have a number of mirror Feed2JS sites that can provide the exact same service as we provide here.
I had not come across a Glog before, but this particular one is full of resources for teachers and is kindly offered to others on the wiki created by SJCCTeacherResources (found via Twitter (@stacybodin).
You put your mouse over each section and a pink circle is drawn round the link taking you to a list of specific resources. Do go and have a look for yourselves. There is bound to be something of use to you in this list..