Can No Longer View Apngs In Firefox

For anyone who doesn't know what an APNG is,

https://en.wikipedia.org/wiki/APNG

I was able to view them just a few minutes ago. Now all of a sudden, every time I try, I get a box saying do you want to open this file with Firefox (default) or save it? I don't need to save it. It's already on my computer. I just created it on my computer and that's where I'm opening it from. If I select open this file with Firefox (default), I get a box saying do you want to open this file with Firefox (default) or save it?

Please help.

 

Sorry. Don't think you read my post properly. I'm looking for help opening APNGs with Firefox specifically.

 

Yes. Just as I said.

 

OK. I feel I'm getting somewhere now. I clicked, in Firefox, on Tools, Options, Applications, and, in the search field, typed apng. In the action column, it said Use XnViewMP which is what I'm using in the meantime. But if I click on the down arrow and try changing the app to Firefox, it stays stuck on XnView. If I pick another random app, say Irfanview, it'll switch to Irfanview. But if I try switching to Firefox again, it stays stuck on Irfanview. Even if I right click on the apng, and select Properties, and try switching the default program to Firefox that way, when I next double click on the apng, it'll seem to start opening in Firefox but then it actually opens in Irfanview. What is going on? Why can't I get an apng to just open in Firefox?

 

This is interesting. An apng WILL open in Opera, Chrome, AND IE. It doesn't animate in any of those because Firefox is the only browser that, by default, SUPPORTS APNGs. But it does at least open in all of them as a still frame. So how come Firefox, the only browser that actually supports APNGs, suddenly won't open them by itself? What have I done wrong and how can I fix it?

 

Even if, in the action column, I select Application Details, and remove any programs that are listed, and THEN change the default program for opening APNGs on my computer to Firefox, if I then go back to the action column, the only options are Always ask (whether to open the file or save it), Save, or Use other. I cannot figure this out on my own. Firefox is the only web browser that has built-in support for displaying APNGs on its own, without any other programs, and I cannot get it to display APNGs. I can only get it to ask me if I want to open the file or save it, save it without asking me, or open it in another program.

 

It's version 44. I started having this problem just before I updated though. Was hoping the update might solve it. But it didn't.

 

Still haven't figured this out.

 

Have you tried associating PNG files with Mozilla Firefox?

 

I've discovered that animated PNGs with the .png extension will still open in Firefox, no problem. It's any with the .apng extension I'm having trouble with. I did try to associate them with Firefox but no good. I still got an infinite loop. Would you like to open with Firefox or save? I select open with Firefox. Would you like to open with Firefox or save? I select open with Firefox. Would you like to open with Firefox or save? I tried this add-on called InlineDisposition which is supposed to force a browser to open any file type it can. But even with that installed, Firefox still asked me to open or save. So I just switched the default action to open with XnViewMP. That works OK. What I really don't understand is if I posted an image with the .apng extension in a forum, I'd see it in the post no problem. I know because I've tried. So I don't understand why they won't open in Firefox otherwise.

 

I'm just confused why .pngs will open but not .apngs. It's just now I want to understand what the difference is.

 

The problem is the .apng extension which is not popular. Most animated png files use the .png extension.
Change the file extension to .png. I just checked and animated png files with the .png extension do open in Mozilla Firefox 42.0.

BTW Where do these files come from? I have 3 and they all have the .png extension.

 

Thanks for the info. I deliberately changed the extension on a file to .apng so I could open animated PNGs separately in Firefox, like I do gifs, and continue to open still PNGs in XnView. But now I'll just change it back. Thanks again.

 

That makes good sense.
In the good ol' days of Windows XP, it would have been easy to do this.

Edit:
I just changed the file extension to .apng and... it opened in Mozilla Firefox 42.0!

 

That's bizarre. I can't possibly get them to open in my version, 44.0.