Nice pic of Fujisan. You will need to fix them by just creating new ones.

In windows now, if you right click on the icon and then go to properties. You should see this option. see screenshot

ive got that far, but the generic icons are very basic, and when I go broswe I cant find any icon files

You will need to browser to the Firefox.exe file, but the easiest way is to just click on start, type firefox, and then drag and drop the icon.

thanks for all the pointers so far just done the firefox 'app' bit and dragged the gmail inbox icon to the desktop. RHS you can see its there but still just blank

Just to go spotify website and then drag the icon to the desktop. see screenshot

Sorry, I'm being a pain I know. But Ive done that, dragged it. Its the same, the icon is there, and the link works, but no image????????

Interesting... I'm in linux now, but can you right click on it and see if the option to open with is there. If so, select Firefox and if there make default.

Sorry, I'm being a pain I know.

Got it... In windows now... Open Windows Explorer, go to your desktop, and look at the files in detailed view. Then you can right click on the shortcut with no icon, then open with, and then click Firefox. I was trying to get a screenshot, but snip tool go BOOM.

where now?

Your screenshot shows that it's already associated with Firefox. Now just right click on the icon, click properties, and then click on the tab Web Document. Then you should see the button to change the icon and then browse to the Firefox directory. see screenshot

.....

Ok thanks Im there. But that only gives me a limited number of options as shown in your attachement. No option for gmail, google photos, spotify etc?