pasted animations?

I've had a Mac Book for 4 days now, I'd never used apple before and I love it, its the best thing I've ever worked on. I mainly got it to do some shopping and basic animations. I have done a few in Photoshop elements but had a question and wondered if anyone could help. So far I've done them where you draw onto a photo and simply duplicate the layer, then go to save for web and it is a nice quirky animation. I have two questions,
1) when I copy and paste from other photos, it doesn't work. Rather than the pasted item showing on the original photo, it shows just the pasted item, and not the original. Why is this and how can I get it to recognise the pasted item? I want to be able to paste stuff onto a background photo and it all to show when animated.
2) can I speed up / slow down the rate of the slides being shown i.e start slow then go quick then back to slow..

Many thanks for any help you may be able to provide..

1.) What size are the photos that you are pasting? It could be that they are simply larger than the background and when you paste them it covers the background layer. Try the Transform tool to resize the pasted item and see if that helps.

2.) If you want to show speed differences, then you could just add more duplicated frames for the slower parts, and less for the faster parts. For example, let's say you have 30 frames of an animation. You want it to start slow, then speed up, then go fast again. One way of acheiving this is: Show 5 copies each of frame for frames 1 through 10, then only 1 copy of each of frames 11 through 20, then back to 5 copies each for frames 21 through 30. You actually end up with 110 frames, but you get your desired effect.

.. thanks for you tips..

the photo I was trying to paste was actually only a small part of another photo. I magnetic lasso'd it, copied and then pasted on the background image.. when I played the animation, the background image was there until I pasted, then it dissapered and the small thing i'd pasted was the only thing on the screen.. Its like it wont show them together, its either the image without the paste, or just the paste. I don't know if its down to levels, all visability was turned on etc, so I'm at a loss as to why it wouldn't work..