Okay I’ve just come across this curious message when trying to open what should be a perfect JPEG image in Photoshop :
“Could not complete your request because an unknown or invalid JPEG marher type is found.”
I checked the file again by using Windows Paint to open the same image and got no error message it just works…
So how did I get there and how is it resolved? Well it starts in Adobe Acrobat with me saving one of the pages as a JPEG…. but I noticed when looking at this problem that instead of the progress bar saying “Saving as JPG” it says “Saving as PNG”!
Ah ha, but the file extension is still saying it is a jpg…..
To open your images you need to rename the files extension* as a PNG file, then PhotoShop can open it without complaint. I guess ‘Paint’ is not as picky about its file extensions as a big professional photo editor such as adobe… Still this is a potentially very annoying bug…
*you may need to change some settings in the Folder Options dialog found in the Control Panel, Click the view tab and then uncheck the tick box “Hide extensions for known file types” now you can rename your files extension type easily.