Peter, first of all don't worry about the size of the images you posted...if you click on the image it jumps up to full size.
As stated, artgalry.exe is a legitimate part of the Office suite of which Powerpoint is a part, but it has been known to hide a nasty trojan......so a good antivirus/anti malware scan would not go astray.
If that comes up clean, fire up Powerpoint, have your Office installation disc handy in case of need, then go Help>detect and repair..............and let it do it's thing. Hopefull it will repair what appears to be a corrupt artgalry.dll file.