Do you mean a digital image file? Or a paper print, or what? If digital, what is the file format? What three characters come after the dot? (as in 'file name.???')
If you are using Windows you might need to go into folder options > View and uncheck Hide extensions for known file types (or similar to that)
As to what will open it... Do you need to edit it, or just resave it as a JPG? I see you do need it to be a particular size. Picasa might do that, and it is free. You'd need to read the instructions to work out how to do it though
Thank you for your help. However, I did download Picasa, and their program could not open my file, which I can open in Word without a problem. It is a .doc file with a photo. But neither Paint, nor now, Picasa, can open this file. It is a 1997-2003 Windows file. I wish I could make it a JPG file, but I keep coming up losers on this. If you think of anything else, please let me know. I do thank you for your help very much.
Since you don't have the linked or embedded original image file you can then zoom in on the picture on screen so that it looks as good as possible, then do a screen capture of the image. That will save it to your computer as something you can now open and edit in Photoshop and most likely Paint and any of your other programs then edit to save to the pixel dimensions you want as a .jpg.
Thank you very much. I am trying that now. I am waiting for Photoshop to finish loading. Paint still could not read my photo. I am hopeful that Photoshop will be able to. Thank you again so much.
And if that doesn't work, last ditch effort, you can get the image showing as large and as nice as possible on the screen and take a picture of it using the best camera you have or even a phone camera. The important thing is to get an image file where you have none now. Right clicking on the image would normally give you an option to save it to your computer but I think all you have now is just the display part of an image you do not have the source file for.