On top of that, when I entered into TiledGGD to look at the files, they came out monochromatic and stretched out. And I know almost next to nothing about using this program, despite RHDN having a screenshot of the program looking into one of the DS games
Those files only contain the raw graphics data. You still need to set the proper width, height and the palette.
The easiest way to find the palette is by running Yabause then going to Debug -> VDP1

Notice also that the image uses 4BPP color mode (4 bits per pixel, in other words each pixel occupies half a byte, so each byte in the file corresponds to two pixels in the image).
Each 4 bit value can only go from 0 to 15 so instead of containing a color, each pixel uses an index to one of 16 entries of a color palette (also known as CLUT, color look-up table).
Take note of the offset to the color table.
Then you close that, go to Debug -> Memory Editor, select the "VDP1 Ram" tab and press "Save tab".

Now you open one of those images in TiledGGD. Most of the default settings are already good for this game.
Go to File -> Open graphics and select one of the decompressed image files (or just drag and drop the file onto the the application's main area).
Go to File -> Open Palette and select the VDP1 RAM dump that you saved earlier (or just drag and drop the file onto the application's bottom right area).
Then you have to select the proper offset to the palette in the VDP RAM dump.

Now perhaps you should look up a tutorial on how to use TiledGGD.
Basically you use the arrow keys to adjust the dimensions of the displayed image (the amount changed is set by the "width skip size" and "height skip size" options).
Page Up and Page Down scroll through the file (not necessary for Maria and Richter's files but required for some of Alucard's). The amount that you move is set by the "Skip size" setting.
You should also set the Palette skip size to 16 colors if you want to check out other images or other palettes since most of the graphics in the game use 4BPP mode.
Home and End scroll through the palette file.
As you can see it was in this game that they decided Richter would have a jump kick, though they didn't actually implement it.
