@ilan How are you measuring the memory use?
You have seen the “Why does ImageJ not release any memory back to the system?” side bar of this Troubleshooting section, right?
Those two facts are unrelated. You can use the JVisualVM profiler to troubleshoot the memory use without needing to use your plugin.
No, Bio-Formats is a library for reading life sciences formats, and converting them to the OME-XML schema. It is not a general solution for image formats beyond that. The general image I/O solution for ImageJ2 et. al is SCIFIO, which has a Bio-Formats format plugin. And the even more general I/O solution (not necessarily images) is part of SciJava Common.