Optimum photo sizes for Weebly?

In the process of creating my website using Weebly. I played around last night and got a few pics uploaded. I'm concerned that as they are full size jpegs they are much larger than they need to be which will impact on the loading speed.

Couple of questions.

What size should I be resizing them to to maintain quality?

How would I do this 'easily'? I have maybe 60 photos so far in various sections.

Cheers

I resize mine down to 1000K when I export from Lightroom, It seems to do fine. If you are using the free side of Weebly, there is a max to the amount you can upload, so the big files were taking up way too much space for me. I haven't had any problems at 1000K, and you can make your slideshow bigger or smaller as well, so the images aren't out of proportion.