HOW TO IMPORT RPGM2K3 GRAPHICS INTO RPGMVX IN A FAST AND SOLID WAY

This is a significant design choice. You can merely double-size the resources in your favorite image editor if you want to maintain the SNES look, however there will be items that show in a higher resolution, like text, and inconsistencies with animations or pictures that use re-sizing effects within the engine.

You can also upsize SNES content with a filter, like 2xSAI. There's utilities floating around that will do this for you, which you then just have to cut up and arrange to be used in VX's engine.