The image format supported in popular browsers: BMP, SVG, JPG, PNG and GIF. There is no two format jpeg or jpg, it's one with multiple extensions used due to see here.
Note: SVG(Simple Vector Graphics) can produced much smaller images but allows only vector images(no raster).
Next, the other formats used are webp and jpeg2000.
Webp:- Supported by many browsers such as Chrome, Opera. There is an issue running for Firefox support here. Note that, Webp can reduce the image memory size to around 30-40% of the original size(in our experiments) on an average. This doesn't means always as sometimes we have seen transcoded webp from jpegs to go beyond the original jpeg size. The output image had no visual difference compared to original jpegs. My suggestion: serve webp where possible, i.e. Chrome, Android, Opera.
JPEG2000:- This format is great. Resizing an image does not drop quality as much as JPEG. The problem is it's too computation intensive for decoding and the fact it came over a decade ago when hardware wasn't great(especially not meant for mobile). It still is used in some cameras as it results in smaller images.
Less popular but worth mentioning: BPG and FLIF. This will require using JS or other library to serve on web/app.