I was working on some .tif images and when I saved them with "save as", the associated thumbnails would be odd. This just started happening so I went through step by step to see if I could isolate the problem. It turns out that when I went to save the file in .tif format, the "save as" window asks for the name of the new file, as is normal. But there are boxes that can be checked below the file name, one of which is "Alpha Channels".    Here's what happened...It appears I accidently checked the "Alpha Channels" box located under the file name when I saved the file. The file saved properly but the associated thumbnail was blue with the subject of the file in black. This box remained checked through several file saves.   Make sure that the "Alpha Channels" box IS NOT checked when doing a "save as" and the new thumbnail should appear as it should. I've attached a sample file which shows the incorrect thumbnail.   I hope this helps anyone experiencing this annoyance. ... View more