Hmm, usually Firefox prefers to show a JPG file in a tab.

You can review/revise Firefox's download handling on the Settings page. The following article has the details:

Manage file types and download actions in Firefox (section titled "Changing download actions")

That should cover many types of files -- can you find JPG/JPEG there?

Thanks jscher2000. I looked at this before posting the question. I did set everything to ask, but jpg is not listed there. It was opening fine, and then all of a sudden, earlier today, it's not. It keeps prompting me to save, instead of just opening. I hadn't changed any settings myself. If I can't figure it out, I'll have to switch to a different browser, although I really don't want to. Firefox was my favorite before this issue.

Does it matter where you download the JPEG file from? Some sites may use a non-standard content-type to bypass the image being shown in a tab as a method to force downloading.

Can you share a public link to an image with this behavior? Please break the link with a space before the .com (or other top level domain) so your reply doesn't go to the spam link moderation queue. For example:

https://www.example .com/favicon.ico

Unfortunately I can't share the links because they're from my children's online school platform, and links sent to me from contracting companies, for work. However here is an example of the types of links. Documents and pictures get uploaded and shared as links. Documents are downloaded as pdf, and pictures as jpg. Both types was giving me the issue, however the pdf was fixed by the steps mentioned previously. The jpg on the other hand isn't listed, so I'm not sure how to fix it. They both were downloading and opening, without requiring me to save previously, so I'm really confused as to what changed.

Maybe I should be referring to them as files instead of links. It's as if you uploaded a saved picture file, from your laptop, to a platform for me to view. I then click on the uploaded file, and instead of it opening, it prompts me to save the file, vs allowing me to just view it. Hopefully this explanation is more helpful.

I have the exact same problem. There is no jpeg listed. I want to see the pictures by opening them rather than downloading them.

What happens if you right-click the file, do you get some options?

Dhpjason I solved this by setting the portion right above your pic to download instead of always ask to save. Make sure the portion that your pic shows keeps the PDF portion as always ask. When the pic is downloaded, you will have to click the download at the top right of the screen. It doesn't open automatically like it use to, but at least the jpeg opens without having to save the file. You'll have to clear your download folder from time to time, because all downloads are stored there.

If either of you would consider using an add-on to help work around this, you can take a look at mine here:

https://addons.mozilla.org/firefox/addon/content-type-fixer/

To turn it on, click its Zzzz button on the toolbar. Then click the button again to open the menu. To override the forced downloading of JPEG images (to allow Firefox to open them in a tab with their original URL in the address bar), change the two settings shown in the attached composite screenshot.