Selecting the images for the gallery

Hi!

I need to find a way to add images to a post, but only some of them will appear in the gallery.

For example: I’ve uploaded img1,img2 and img3, inserted img1 to the post and added the gallery. The gallery would show only images 2 and 3.

I’m thinking in create a custom control (a checkbox) that would mark what images will be shown in the gallery. Is that possible?

Thank you!