How come I can mesh a photo but cannot reshape it?

I placed a JPEG picture in Adobe Illustrator CS2, and then trying to reshape the rectangular photo into some sort of a perspective polygon. I could not make it work since "Direct Selection tool" (white arrow) did not allow me to select a corner of the JPEG and move the corner point by dragging it. I could easily do that to a real rectangle polygon, though. I used Direct Selection tool to select a corner of a rectangle, and I could move the corner to turn the rectangular polygon into a trapezoid.

This is a bit frustrating. How come I can make a rectangle into a trapezoid but I cannot make a JPEG photo into a trapezoid? In fact, I can twist a photo into some very funny shape by [Object]->[Envelop Distort]->[Make with Mesh...]. But I want some simpler. I just want to free transform a JPEG into whatever polygon shape I like.

The reason I need to do all this mess is because I need to combine a bunch of small photo together to form a big photo, and I need to twist the perspective a bit since the source photos I got was taken with a bit tilted perspective, and this I need to do some reshaping to compensate the tilted angle.

After several frustrated night, I found out that I can accomplish the effect by using [Effect]->[3D]->[Rotate...] and then resize the photo. Not the most intuitive way, but heck at least I can get the job done.