One of my graphic designers made some animated GIFs for an email campaign. They have a lot of frames, and some of them are 2 MB. I used an image compressor and got it down to 1 MB, but I'm wondering if even that will be slow to load?

I'm not that familiar with best practices for image file sizes since I usually just use JPEGs and don't worry about it. Would 2 MB be okay? If not, what size should I aim for?