Meme Generator online are legion, and they do not offer the same options. Most will limit the size or shape of your meme, and most will apply their signature stamp on it. Plus it takes time to upload the image, refresh the page etc.
There is a solution for you though, and pretty easy believe me! It’s based on ImageMagick, with a simple drag&drop batch script for Windows. This solution will let you create classy memes even your mother would be proud of!