#fpacatuto asks

Actually, you can just use Space Bar and drag your mouse to do the same thing! 

And if you press Shift+Space Bar and drag, you can rotate the canvas, without using the navigator window. Same thing works with Alt+Space Bar!

Ctrl + Space Bar and mouse drag is zooming in/out!

This wasn’t asked about, but a useful similar shortcut for changing your brush size is Ctrl+Alt and drag while in brush tool  (without actually permanently changing it for next time you open the program). Super helpful when you need a painting brush to be just a little bit bigger for a few strokes.

for bitmap brushes, yes, you can make a slanted brush (lets say you make a round black circle (e.g. pen brush at 200px size) and then transform it to make the shape flattened. Then when you use that as a bitmap brush, there is an option to "rotate along" the brush (it will turn along with your strokes, not stay in place), as well as change the angle via "rotate angle". This way you can make marker and calligraphy brushes for yourself, for example.

It seems that your texture file might be smaller than the image you have created. It could also be that it has a different dpi (dots-per-inch) property from your created file.

Usually, images downloaded online have a dpi of 72 or 96. You can try changing the dpi of your created image to the same as your texture (you can see this when you open the file and use the menu Image>Image size) or you can also resize the texture layer to fit your created images(Ctrl+T and drag from a corner). This should make the texture file a bigger size. If it's something that's closer to a photo in texture than a drawing, it will not be too noticeable in the final image that you have scaled your texture(especially if the layer is set to overlay/other layer modes).