You can't. One of the limitations of the chip board is a definite (and intentional, I think) inability to edit/change anything that's already been posted. The best you can do is PREVIEW your post before sending it and if it doesn't look right, delete the image you uploaded from your post, do what I suggested, and reload the image and it should be right and THEN you can post it. If you accidentally already posted something in error, you can either leave it (we all understand that "it's a thing") or you can delete your post and make a new post.

Now, since you're simply sharing your lovely collection, might I suggest you post it on the CCA message boards? There, you can edit, change, use more smileys, do quick replies, and give/get likes without having to do a reply at all. It would also add some wonderful content to that board. You won't lose any/many viewers because you can post a link to your CCA post here. People can just click and view. Well, that's my sales pitch for the day. I love what you have collected. Keep on sharing!