This is an easy tip.
Twitter and some other sources use a jpg-large file format.
If you cannot open this file format, simply remove the large designation at the end of your file name and it should open immediately as a jpg file. Make sure your file ends with jpg and nothing else.
There is no need to figure out how to convert this using any of your programs, or an image converting online service.
Here is a link to my other hot computing tips: