Hmm. My first feeling was the same as yours, but the more I thought about it, the less convinced I was. If it were "Save your scrapbook.com images", there would be no question of a possessive, but I think because "peas" is plural, and because they refer to themselves as peas, there's an instinct to make it possessive as well. They have already captured the possessive in "your".
I hadn't dissected it quite like that.
What if you are saving photos from your two brothers? Would it not be: "Save your brothers' photos." ??
On the other hand, you wouldn't say, "save your Facebook's images."
You may be correct.
(I love these discussions. )
"Save your brothers' photos" has two possessives, (not to mention two plurals). The brothers belong to you, and the photos to the brothers, so you'd need the apostrophe in "brothers'". The photos are not yours in this case.
But in the sentence "Save your Two Peas images" the images are yours, they don't belong to Two Peas. "Two Peas" is just an adjective that describes the images. I think that's the grammatical explanation. Did I get that right?