Picasso, while often burdened by being the straw that breaks the camel's back in terms of memory and OOMs, is basically never the actual cause of the problem. The library is dutifully trying to load the images you tell it at the size you tell it (either implicitly or explicitly). Your app has pathological memory problems that caused the heap to fill and images no longer are able to fit.

Try something like LeakCanary to see if you have memory leaks, or do general memory cleanups like using smaller original images and .fit() to size them, use RGB_565 for photos to halve their memory requirements, and in general use more memory efficient data structures such as those provided by the support libraries.