Picasso’s library size is smaller than that of the others, but a first-time image load can take much longer. Its main advantage is that it is extremely easy to implement in app code—typically one line. Thus, it’s best for apps that need a small memory footprint and don’t have to process lots of large images.
Glide’s loading times are faster and it uses a small amount of memory for cache, but the library size is quite large. It, too, is easy to implement. Glide might be a better alternative to Picasso when memory footprint is less of a concern or more and larger images need to be processed.