This tutorial will tell you what you need and how to make small portraits for your character.
First, download XnView from: http://www.xnview.com/en/xnview/
Now open up your character in fighter factory and find the sprite you want to convert to use as the small portrait and extract the pcx file.
Next open up that image in XnView, use the zoom function to whatever size it is easier to see what you do.
Then take the cursor on the sprite to whatever 25x25 area you want to use.
Look in the menu bar for edit and scroll down to crop.
Finally just close out of the program making sure to save your work. Unfortunately the 'save' and save as' function won't work normally, so just closing the application is the way to save it because when closing the program, an option will come up then about saving your progress.
Now just insert the new file at the end of the sprite file, making sure it is aligned to 0x0 with a sprite number of 9000,0. You will also have to change the previous 9000,0 to something that will not be used.