My image is very wide, and though I could crop into it and just focus on the woman's body, at this point I think I'm going to keep most if not all of the image - which will mean some kind of elements (possibly just solid colored bars) to occupy the rest of the cover.
So I'm going to scale the image - but first, I want to lay out some guides - a feature that's lacking in low-end image manipulation programs (sorry, Paint fans). So I turned off the layer containing my image by clicking the eyeball to its left -
Then I dragged down two horizontal guides by clicking on the ruler at the top of my canvas and pulling down.
I'm not totally sure that I want to divide the cover into even thirds - that might be too boring - but I think it's a good starting point, especially considering the dimensions of my image. So I dragged one guide to 800 pixels (1/3 of the 2400 pixel height of my canvas) and another guide to 1600 (2/3 the height).
Now I've clicked the eyeball again to turn my image back on. I want to size it so that it fits into that middle bar - as close as possible anyway - so I clicked GIMP's Scale tool - the one highlighted here in the toolbox:
With Scale selected, I clicked on the image in my canvas and I saw this box pop up:
Why is this important? Stretching a photo (or a font, or an illustration) vertically or horizontally is something that can immediately make your image look less than professional. Our eyes notice the distortion immediately, and it rarely works to our advantage. So always scale your images proportionately - if you're using a different program, do some research and find out how to do it. Because usually, once you distort your image, you can only get it back "by eye", which is never going to be perfect.
So I clicked the link and entered 1600 (the width in pixels of my canvas) into the first field. There's no need to enter a number into the second - because the Width and Height are linked, the Height will be the proportional dimension to the width we entered. Just click the Scale button (which really should say "Okay" or something similar) and let the program resize the image.
The first thing I notice once my image resized is that the new, smaller image is outside my visible canvas. I had to zoom out to see it - you can do this either under View > Zoom in the top menu or by using the magnifying glass icon from the toolbox (hold Control/Command and Option and click to zoom in and out).
I see that my image is not only off the canvas, but it's only visible as an outline (remember, I'm using GIMP for the first time for this project). I'm fumbling around without Photoshop (but it's a good challenge).
I click the Alignment tool next, and the additional options below appear:
Then I clicked the upper right tool in the Align section (Align Right Edge of Target) and part of my image became visible on the screen.
And I clicked the Align Middle of Target button - and my resized photo moved to the dead center of my canvas. From the top menu, I clicked View > Zoom > Fit Image in Window so I had an ideal view of my layout:
You can see that the image goes a little above and below my 1/3 middle bar. Should I change my layout to suit the image or should I crop the image? I definitely don't want to lose the woman's hands - and cropping into the fence area seems like it would be awkward.
For now I'm going to by pass that decision by just leaving the image as it is. No need to crop it now - instead, I'll cover it with another layer.
In my Layers panel, I clicked the lower left icon (looks like a piece of paper with one corner folded over) to Create a New Layer.
From the window that popped up, I named my layer "Black Cover" and kept all the other settings as they were.
Now I have a new layer to work with. Incidentally, that little checkerboard pattern in the layer thumbnails shows transparency - that's how you know it's not filled with white.
With my new Black Cover layer selected (that blue highlight across the layer means you're working in that layer), I go to the top menu and click Edit > Fill with FG Color (FG means foreground - it's the top color in the two rectangles with the arrows at the bottom of the Toolbox).
And I have... a totally black cover. But that's okay, because you can see that the resized image layer is still intact below it. If you don't believe me, click the eyeball to the left of your Black Cover layer (or whatever you've named yours).
I want to show that image peek through. I could just grab the layer (click the actual layer and hold it) and drag it under the image layer - but I want to keep it on top, in case I want to try out different croppings for the image.
So I keep the Black Cover on top and click the Rectangle Select Tool from the Toolbox (upper left corner). Then I click and drag around my guidelines, starting outside the canvas in the gray area on the left and dragging to the outside the canvas on the right. I've made an active selection, which is what the "crawling ants" border indicates.
Then I cut - Control- or Command-X and the area I selected is cut from my Black Cover. Now I have this:
I decide to keep my Black Cover as it is, with that perfect middle third sliced, and I'll work with my image. I click on the Woman at Fence Copy layer (the program added Copy when I duplicated the layer in the previous step) so that's what I'll be moving.
Something I noticed about GIMP that's not very intuitive - the Move tool defaults to moving Paths instead of Layers with a little icon at the bottom. That's bad. Once you've clicked the Move tool, click the Layer icon at the bottom(ish) left:
Instead, I suggest using the Up and Down Arrow keys to move your image. They'll move one pixel per hit, but you can hold down Shift to move at ten times that amount. I moved mine until the top of the image was right at the cutout I made in my Black Cover layer:
Decisions, decisions. But for right now, I'll leave it as it is. The next step will be Fine Tuning Your Image.