Absolutely, Del. That's precisely what layers are for, independent manipulation of each image element.
It sounds like you're brand new to Photoshop. I'll give you my standard introductory speech. You're probably not gonna like hearing this, but ignore it at your peril. Slow down. Learning to use Photoshop (or any other piece of graphics software) for the first time, and learning to texture for 3D are two different things. The latter obviously depends upon the former. Trying to learn both at once is almost always a formula for disaster.
So take a couple weeks doing strictly 2D projects, and get to know Photoshop itself. Then, only after you've got a firm grasp of the fundamentals, come back to learning how to texture.
Trust me; should you continue trying to put the cart before the horse, you'll regret it. Think about how this missing piece of knowledge here has slowed you down. Now multiply that by 10 for every step further into texturing you try to take without knowing the simple basics. Get the picture? A few steps in, and you're gonna find yourself tearing your hair out and smashing your keyboard to bits. Take a few steps back, learn the basics, and you'll be able to tackle this stuff in no time when you return to it.
As for your specific question, and its presence on this forum, just so you know, many would argue that such absolute beginner basics are well below the scope of a forum that focuses on a the high level topic of texturing for 3D, and they'd be right. This isn't a Photoshop 101 forum (there are lots of those out there); it's a texturing forum. That doesn't mean you should be afraid to ask; just be aware that some may chastise you for being "off topic".
So, my first answer to your question is to tell you that you should consult the basic introductory Phototshop Help. The sections you want to read for this subject are Workspace and Retouching & Transforming.
I'll also give you some very basic pointers right here (but don't let this stop you from reading the help; you absolutely MUST do that). See the Layers palette in the lower right hand corner of the screen? If you don't, then simply go Window -> Layers and it will appear. See how it's got all the names of the layers in a stack? Click on the name of the layer you want to edit, and it will highlight, indicating that the layer is now "activated" (a fancy word for "selected"
.
Now go Edit -> Free Transform (or use the keyboard shortcut Ctrl-T). You'll see a bounding box appear around everything on the layer. Drag the corner handles and edge handles of the box around the screen, and you'll see everything on the layer resizing to the new shape of the bounding box. To scale uniformally, hold Shift while dragging.
In addition to dragging the bounding box handles, you can also transform "by the numbers" via the tool settings bar at the top of the screen. Take a look at it, and you'll see fields for X & Y pixel dimensions, height & width percentages, rotation angle, and skew angles. This is very similar to the way the Object tab works in the Editor window in SL.
I hope this has been helpful for you. Again, I'll say (for lack of a better term) RTFM. Learn how Photoshop works before you try to learn how to texture. If you've got a specific texturing question, ask away, and lots of people will jump to answer you here. But if you've got questions on getting started with Photoshop, be aware that 99.999% of people are not going to take the time to help you here, as it really is off topic from what this forum is for. Good luck.
