[SergeNL]

5b.* Main Image. (top-left window “Images”, section “Main Window”.)
The background image is an Image-file in the Skin’s folder, usually called “Main.bmp”.
It may have any name, but if Skin.ini doesn’t specify a name, it assumes it is “Main.bmp”.
Top-left you see the folder location of Main.bmp. That subfolder contains all Skin files.

Changing the image is easy. Find your own BMP-file. Copy it to the (sub)folder.
In Skinmaker, use the Browse-button to choose your new image. Save changes (F5).
If the image is too small, some buttons will not show. Resize and edit it in a photo-editor.
Better is to rename your new image to Main.bmp, replacing the old one.

Main image in JPG-format?
Skinmaker supports JPG, but BS.Player does not. (GIF files don’t work too.)
I tried it.. The Browse Button for the Main image in Skinmaker does not show JPG-files..
But you can add the name of the JPG-file manually in Skin.ini, on the 6th line.
Now Skinmaker will load it, and will even save changes.
But BS.Player does not load it, and will use the main Image of the Base-skin instead.
Change the extension in Skin.ini, or in Skinmaker’s Buttons-section didn’t work.
(Same story for buttons. You can load them in Skinmaker, but BS.Player can’t handle them.)

The “Any Shape” checkbox is not checked. The Skin will show the whole rectangular image.
But Skins can have any kind of shape:
The main image will still be a rectangle, but part of it is completely transparent and invisible.
In “Any Shape” mode, everything with the same colour as the top-left pixel will be invisible.

Changing the colour of the top-left pixel by editing or replacing Main.bmp, can be a problem:
Skinmaker will do fine after reloading the skin, but BS.Player may still use the original colour:
The result looks terrible: the new invisible-colour suddenly is visible, and there may be gaps.
In Explorer, go to the folder of the Skin and delete rgn.dat and rgnfs.dat. Reload the Skin.
These Dat-files ‘remember’ the invisible colour, to speed up the process of loading a skin.
You can delete them, because BS.Player will generate new ones, when it uses the Skin.
(So use folder-skins at least once before making a BSZ-skin out of it. BS.Player can’t edit BSZ.)

To change the colour of the transparent area in Skinmaker, as displayed in the image:
Double-click the area and pick another colour. Or right-click it, to restore the default colour.
This only changes the view in Skinmaker for comfort during design, so not the Skin itself..
The colour BS.Player uses for transparency will always be the top-left pixel of the BMP-file.
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