Well, sounds like you already know it's going to be too small for you. To guess the size based only on the photos, not knowing the wheel size, and in the absence of tires, well... Assuming 26 x 2" balloon tires, it's a pretty small frame, like 21" or so. But this style of bike is made for a very upright riding position, where size is not so critical... so with a longer seat post you may be comfortable enough on it.