This will be fixed for Mac in a next Firefox version. A workaround for now is to save the image using "Tools -> Page Info -> Media" or via the right-click context menu instead of dragging the image.

• bug 1389836 - Saving images via drag-and-drop loses filename extension

(please do not comment in bug reports
https://bugzilla.mozilla.org/page.cgi?id=etiquette.html)

Thanks cor-el. I've seen that. That workaround, though, doesn't address the problem I had with Firefox 57 changing the application associations on ALL the images on my hard drive (and any external drives I might have connected.) Until that's fixed, there's no way I'm upgrading beyond FF56.

Why on earth would Firefox even touch my system settings?

I also forgot to note that, randomly, when doing a "Save Image As..." the Format toggle at the bottom of the Mac OS dialog window would change from "Preview (default)" to a generic "Document" format, and there is no way to change the toggle back to Preview. The only fix is to quit Firefox57, restart, and hope for the best.

No the option is since was a bad update in my opinion is to do a : uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Note: your Firefox Profile is saved. But you should make a back up before you do : https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Reinstall with Current Release Firefox 57.0.2 with a Full Version Installer https://www.mozilla.org/firefox/all/

As for touching "your settings" Must remember there is a terms of use. Firefox can do anything within the terms and force updated everyone. You are not alone. 56 is now a discontinued browser as is everything below and will not get any updates or security patches. If need to, go to the Extended Release Version 52.5.2 ESR as it gets updates and patches. The 58 Release should not be too long now.

Sorry to hear your image extensions got changed. There are programs that you can use to batch change them back.

Please let us know if this solved your issue or if need further assistance.

Well, this problem isn't fixed in v58. Firefox is still changing system-level file associations. In this case, it changed all jpeg files on my local drive to open with Adobe Illustrator instead of the Apple system default, Preview. And there was no dragging/dropping from the browser involved. Firefox has no defensible reason for screwing with system level settings like this.

Having to change the associations back to their proper defaults several times a day is preposterous.

I use Photoshop and through MacOS 10.13.3 associate my image files with it. Sometimes while saving an image file in 58.0.2, Photoshop is removed and Preview.app shows up in the dialog. The file extensions are untouched.

Running a Get Info on the file shows Photoshop was removed from the list and my jpegs and pngs are assigned Preview.app When I say randomly, I can visit the very same page and it will save normally as a Photoshop association.

I've been pestering Apple and sending them Capture logs because I was blaming High Sierra, until someone in Macrumors mentioned FireFox as a possible source.

Note: It happens randomly in MacOS 10.13.3 but never in 10.12.6 both on mid 2012 Macbook Pros. Manually adding Photoshop or doing a safe boot restores the default. If a image needs work, I want to double click it on the Desktop and open it in Photoshop.

I see this topic and I hope this is the answer. As a plain old user, I have no idea on whose programming property this falls on or who needs to fix what.

I really love Firefox for the functionality the add-ons give it and switching browsers is not what I want to do. I can stay with 10.12.6/FF 58 for piece of mind and see if an update from either side makes it go away. Other than that if you have any advice, it is appreciated. I'll review the answers in this thread.

Thanks for listening, Gene

File associations broken in both Quantum and Nightly in macOS.

Strange. It's ok in MacOS 10.12.6, but not 10.13.3

I hope they can fix it.

Gene