This is how I do it in Photoshop:
1.) Pick any image that you want to use as a Mugen Portrait, make sure it is a png type. (I use Ryunmei as an example) And of course I remove the background of the image manually using a normal eraser. It's up to you if you add an outline edges on the character or not, for me it looks better with outline.
The Original with [blending Mode = Normal]
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Layer Options:
Encircled in Red is the Blending Mode
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2.) Right Click the Original Image and create a duplicate layer. [Which is Background copy 4] And set Blending Mode = Multiply
As we can see here, the image is bit dark and look suck. So let's brighten it up a little.
In Photoshop go to Filter -> Other -> Then click High Pass as you can see on the shot:
And you'll see a prompt message like this:
Do the same values as what you seen in the shot. Then click OK
After clicking OK the image goes like this:
Looks better now with Blend Mode = Multiply + High Pass.
Note: Sometimes when I use high pass some other images doesn't go like this, if this happens then don't use High Pass just go to Layer Options and adjust the Opacity and Fill of the image to any values you like until you are satisfied with it.
Or you can just SKIP this method and jump directly to Method Number 3. (It's up to you)
Or if you are satisfied with Method 2, then don't do Method 3. (It's up to you)
Or you could do the both! It's actually up to you.
3.) Right Click the Original image once again and create another duplicate layer. [Background copy 5] And set Blending Mode = Soft Light.
The FINAL TOUCH! With Blending Mode = Soft Light. AND YOU'RE DONE!
Right click any image layer and Click Merge Visible, and you're ready to index.
Note: Before indexing or merging the image save your work as a psd file just in case.
Summary: [Comparison]
1.) 2.) 3.)
1.) The Original with Blending Mode = Normal
2.) The 1st Duplicate with Blending Mode = Multiply + High Pass
3.) The 2nd Duplicate with Blending Mode = Soft Light
I forgot about the background layer, that makes it four. There's no need for an outline layer when you can do it on the original image.