Some thoughts on image file formats:
JPEG was primarily standardized as an economical final delivery form for photographs in days of dial-up modems. One can compress the image greatly, but still have it contain sufficient information to deliver the message. When digital cameras came into being, storage cards were extremely expensive, and JPEG provided a viable solution. It achieves its compression by throwing away part of the data - which is not necessarily bad. At the highest quality settings, only redundant data is discarded and every application that can display a JPEG understands this and is able to replace that data. The method by which data is discarded and replaced is a well known standard and reconstructing the data is amazingly effective.
However, the more compression, the less data, and the less successful the restoration. Knowing this, when I prepare JPEGs for web viewing I reduce the resolution to web sizes and I set the compression to just below the level that artifacts become obvious. While the images look great in your browser, they are in fact badly damaged. Should an unscrupulous person decide to use one of my images for publication at any size over a postage stamp, they will look horrible. If any enlargement is tried, or any further image processing applied, artifacts will be horrendous. JPEG is an extremely useful format for display of photographs.
If the file is processed and re-saved at similar high compression settings, the artifacts are multiplied each time this is done. Yet the first generation looks pristine. This does not happen at high quality settings, since it is just redundant information being thrown away and restored. You may be warned against using JPEG for storage, but it is just fine at top quality settings and it will save lots of time and storage space.
TIFF is an extremely versatile specification for storage and many other needs. Digital camera RAW files and two colour fax files for optical character recognition are TIFF based. Another form of TIFF can hold multiple images. Lossless compression is part of the specification, though sometimes it works in reverse and the resulting file is actually larger.
BMP is a simpler form, less common now. I mentioned BMP in the presence of a rather pretentious geek who snorted that it was a terrible file format. I pointed out that I had actually tested it against a TIFF, layering the same image saved in both formats, having Photoshop flag the differences, analyzing the result pixel by pixel. ZERO difference. Image quality was identical down to the last pixel. Bottom line is that while TIFF is a much more versatile format than BMP for application developers, it makes no difference to whatever users. Results are identical.
There are many more older and obscure image file formats that have fallen into disuse, but none have been lost. From time to time, I read people passing on misinformation that one should ONLY use TIFF or DNG because other standards may not be supported in the future. Simply not true.
The knowledge of how to decode them is known to millions and well documented. Files from early digital workstations are still accessible by contemporary applications. A project is underway to rescue early photographs from the space-program. Specifically from exploration of the moon going back the the late 1960s. The problem was that the tapes from the time were lost and recently rediscovered. Once found, required refurbishing drives from that period in order to read them. No problem with imaging. IFF-HAM files created in the mid-1980s on the long gone Amiga computer open fine today in Photoshop.
Information persists. Post a personal and embarrassing image on line, and then try to get rid of it when you sober up the next day! Once a file format has been in use, it will persist as long as any naughty photograph.
As an alternate to JPEG for delivery, specially on-line, PNG is a winner. It provides excellent reproduction of photographs, but also type overlays. JPEG is really poor at this. Any time I do a tutorial on my web-site, annotated illustrations are posted in PNG. The downside is that compression is much less than with JPEG, so pages and illustrations open more slowly.