The best time to learn emergency lifesaving procedures is before you need them, but the second best time is when you need them. Being old fashioned about this could cost a life.
If you have a quicker reference people should bookmark for such cases, the kind thing would be to share it rather than judge. Else, panicking people will inevitably go where they know they can usually get fast instruction about any other topic.
Formats are chosen by the uploaders and hosts, not the end user.
For easy conversion of images from the web, I recommend the FF addon Save webP as PNG or JPEG. Anytime you open an image in its own tab, it pops up with a menu that gives you a quick button to choose the format you'd like to save it in.