I think you're simply using a different version of the browser you were using on your old computer.
When you click the image button, it's simply giving you tags to embed an image that's hosted elsewhere. If you want to upload an image, click the "click here to upload!" link below the posting box.
Aime, my old computer updated something and now it is doing it too. It kind of seems like the posting box here is not keeping up with the updates? it is very difficult to post several images in a post. The text bounces all around when I click the image button, then once I click on it, I have to scroll to get to it/find it.
Another thing I noticed is suddenly seeing automatic linking to certain words. In my necklace thread in the jewelry section, if I type the word Swarovski with a capitol S, suddenly a clickable link appears. I think that is just wrong, it distracted me from reading what I was looking at, wondering what the heck why all of a sudden there is clickable link blue text for the word swarovski like I am promoting them or something. Swarovski is not paying me to promote them but it sure would seem so.
Well now, it happens with a small s too. I do not love this, why is it happening? Do I have to stop posting the word swarovski?