If you have a selection, it will scale only the selection. You have to use the Scaling tool (Shift + S + <click> on image), not the "Scale Layer" menu.
If you want to use Scale Layer for some reason, convert your selection to a "floating selection" (which is more or less a "modal, temporary layer") first, by pressing <...
There's no 'technique' that can be employed when you are discarding 96% of your image data.
You are literally throwing away detail that cannot be preserved in such a small space. Your image is going from 36 million pixels down to just 1.4 million, the rest went in the bin.
The dotted yellow line is the layer boundary. It's not the text box. Also it's not a real line, just a visual guide to show you the extent of the layer.
When you export an image as JPEG/PNG etc, it won't be visible
If you don't want to see it while your are working on an image, either select another layer in the layers panel, or alternatively you can switch ...
Known "problem". The solution is to use the ofn-text-path-selection plugin. For instance
with a path like this:
The regular selection renders like this:
And the plugin instead gives you a selection that renders like this:
The problem wasn't so trivial
Your color change is mostly Blue because the value drop is higher in the Red and Green channel:
So if you only need a monochrome image you can just extract the Blue channel. The easiest way to do this is to open the Channels list, and drag the "Blue" channel to the canvas. This creates a layer which is a copy of that blue layer.
Another technique ...
You could create your template from a group of the card image, with the border on a layer above it, and then add the layer mask to the group.
Then all you'd need to do is import/paste each image into a layer inside the group, but under the border layer. Then you could simply enable/disable each image layer and export as required.
Note: if you want ...
Another way to change the current pattern if your Tool options dialog is not showing: open the Patterns list dialog, either
with Windows ➤ Dockable dialogs ➤ Patterns
by clicking on the pattern preview in the toolbox (if showing, this is set with Edit ➤ Preferences ➤ Interface ➤ Toolbox ➤ Appearance ➤ Show active brush, pattern and gradient)
You can use a layer mask in GIMP (also possible in Photoshop).
In GIMP use the Paths Tool to draw a shape, hit Enter to turn it into a selection
Then hit the layer mask icon, and choose "Selection".
If you want to soften the junction of the two images, you can use a layer mask:
You add the mask to the top layer, initialize to "Transfer layers alpha channel".
You will see in the thumbnail preview that the mask is black where your layer is transparent and white where it is opaque.
Then, painting on the mask changes the opacity of the layer, so ...
I don't know how you can apply "pressure" with a mouse.
One thing that puts some variation on how the paintbrush works is "Brush dynamics":
Make sure it is set to "Dynamics off".
Otherwise, the paint brush interpolates pixels, so slight shakes may some edge pixels darker or lighter. If you want to draw a clean straight line:
There's no equivalent format in GIMP. However you could put .gbr files inside a ZIP folder for upload/download purposes. This has nothing to do with GIMP though.
To create one in Windows, right click your desktop or any blank space inside a folder, choose New > Compressed (zip) folder. Open the zip folder, and copy and paste your .gbr files inside it. I'...
I think he is right the font viewer on Gimp is a total pain. Also I don't want to open yet another program when looking at fonts. Gimp needs a larger font interface that's easier to navigate and shows the fonts more clearly.