First, I don't recommend "hitting" the effects. It can damage your computer.
Actually, what you are using are preset effects. Preset are effects that have keyframed motion paths already added to them -- and, as you have found, they often are designed for very specific size photos.
In order to customize a motion path (or even revise a preset so that it behaves as you'd like) you'll need to tweak the keyframing.
To access the keyframing controls, right-click on the clip on your timeline and select Show Properties. In the Properties panel that opens, click the Show Keyframes button in the upper right of the panel to open the keyframing timeline. From there it's just as matter of moving the keyframe points (the little white diamonds) around or changing their settings to match your needs.
I take you step by step through keyframing in my books. You can also find some free articles and tutorials on the basics on Premiere Elements support site http://Muvipix.com. Just type "keyframing" in the search box.
I take it you are using still images (as an aside what pixel size are they?). So to make it zoom slower you need to increase the time across which the zoom takes place. The simplest way is to select the image and hover your mouse at the end until it shows the drag marker (a two headed arrow that so far has resisted all my screen capture options to capture for use in this post ). Now drag this to the right to make the image stay on screen longer and as a consequence slow down the zoom.
Insanity is hereditary, you get it from your children
You have gotten some very useful replies for doing a Zoom Effect.
As Steve points out, you are using an Effect Preset to get the Zoom.
I feel that one has so very much more control, when they manually adjust the fixed Effect>Motion>Scale and manually Keyframe that Effect in the Effects Control Panel, available with the Clip/still Selected, and then from the Effects Tab>Edit Effects. You are starting from scratch, but it is much easier to just create what you want from a clean slate.
I will second Steve's Basic Keyframoing articles on Muvipix. Initially, the concept of working with Keyframes is a bit abstract, but once one has a full grasp of that concept, the door to so much power opens wide. One can Keyframe many Effects directly, and a few more, indirectly. The mechanics are the same, and that is why an understanding of the concept is so important.
Keyframing is so important for adjusting Audio Volume over time.
I will try this out ASAP>>>> once again, Neale, you are able to "describe"
in the "easiest" way (textually) how to do things on this program. I hope I
it to work well and hence let me use an effect the way It should and/ or can
be used the best
I totally agree that it is far easier and more effective to create certain effects from scratch using keyframes rather than presets. I have been using Elements since version 2 and have only in the last couple of months discovered the true magic of manipulating keyframes in the properties box (rather than just adding them to volume and opacity in the time line). This has been a true revelation and was as a result of a determination to create simultaneous pan and zoom effects which I have never been able to do with presets. Using keyframing from scratch allows you zoom in on a specific area of your still or video clip by typing in values and dragging the image to create motion paths. You are not limited to side to side pans - you can go diagonally or any which way. This can be used to dramatic effect to say zoom in on a person's face in which ever part of the image it is located. But it is not the easiest thing to describe and I got there by trial and error. Practically, this is not a very helpful comment but I just wanted to say it is definitely worth persevering.