Well, does anyone have any idea how to fix this???

I'm assuming then, that it's a problem with the app. I'll use a browser that works.

We actually bring context menu by long press on the image and use "Save image" option. Except when this image cannot bring context menu even on desktop Firefox.

Except when this image cannot bring context menu even on desktop Firefox.

What does that mean?

I don't seem to have this issue with any bother browser. I've never ran into a situation where the browser sometimes brings up a context menu and sometimes it doesn't when long pressing an image.

For example, if image is declared as background image, or javascript is preventing you to copy the content of the page.

I still don't understand. Whatever.

All I know is, when using Firefox, if I open an image and long press it I get no context text menu like I do with all other browsers that I've used.

Try to long press the image on this page: https://support.mozilla.org/en-US/kb/about-tiles-new-tab

Does it bring the context menu or not?

I did get the context on the long press of the image(s).

But, if I tap a thumbnail to open it and then long press I don't get a context menu. When I long press the thumbnail and select 'View image' I do get a context menu.

But again, I don't get one when I open an image by tapping the thumbnail to open it..