A common problem on the forum is that photos open in the incorrect orientation. An easy way to fix this is to use GIMP (generic image manipulation program) which is and open source equivalent of photoshop and therefore free to use.
When you open a file (usually a jpg) it checks the rotation info and allows you to rotate it as required. Use the Export to save it back in jpg form (otherwise it uses its own .xcf format), then it will appear correctly when uploading to the forum.

You can get it https://www.gimp.org/ they have versions for Linux, OSX and Windows. (my recommendation is for the Windows version only- about 194MB download)

I have used this for a number of years and is very reliable.