Affiliate links for Vine items?

I have an affiliate account for an animal nonprofit I run. Am I violating anything by posting affiliate links and pictures of products I get through Vine? I wouldn't be mentioning Vine or that I got the item free, it's more along the lines of....I post a picture of an animal playing with a toy I got through Vine. Someone says hey, that looks cool, where did you get it? Generally, for items I don't get through Vine, I post an affiliate link and let them know the rescue gets a portion if they buy through it.

Now, I would love to be able to sharing pics of someone sleeping a bed or something and just include an affiliate link, but even if that wouldn't violate anything with Amazon, I'm wondering if I would be running afoul of the FTC rules about affiliates and such. If I wasn't posting a review of the item, would I need to disclose I got it free? TIA for any thoughts, I've tried to read the terms, but I admit I got lost, sigh.