Hi Catherine, a "normal" or should I say "Lite" Flickr account holds only 200 images. If you intend to keep adding images, you'll have to go "Pro". Costs something like $29.99 a year, and gives you unlimited space on your own Flickr page.
You can join as many groups as you like, but trust me, you'll soon be whittling them down to 20 or less, as it gets to be a burden having to update each group independently. I think you can only use the same image in 7-8 groups at a time? Don't quote me on this, it's only an estimate, and what I've seen happening to my own images.
Here's how I manage my Flickr account: I accumulate 20 images before uploading to Flickr. Then, for each Group I share to, I just make sure I'm clicking on a different lot of 6 images each time (or 3, or the odd 1). Having a pool of 20 images makes choosing a different set each time much easier.
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