Go from this
to this
in PSP8.
I started with
this image from PoA of the trio and Hagrid down by the lake.
Step One
Crop your base however you'd like, and resize it to 100x100.
Step Two
Sharpen just once. Then zoom in and use the smooth tool to soften any areas that may seem too pixelly.
This image didn't really need it, but I usually do this with every icon I make. Don't overdo it or your icon will look weird.
Step Three
Duplicate your base once and set it to Screen at 92%.
Step Four
Fill the next layer with the color #D3E7E6 and set it to Burn at 26%.
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Step Five
Fill the next layer with the color #000040 and set it to Exclusion at 100%.
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Step Six
Fill the next layer with the color #F5C9A5 and set it to Soft Light at 60%.
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Step Seven
Add this orangey-pink gradient as the next layer and set it to Multiply at 14%.
(I don't know who made this gradient - if you know, please tell me so I can credit them!)
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Step Eight
Duplicate your base, drag it to the top, and set it to Soft Light at 100%.
Step Nine
Make a new layer and add some text. I pulled a dark color from my icon and then used Georgia at size 1 for my tiny text.
I typed something random about Hagrid being emo... you can obviously type whatever you want.
I lowered the opacity of the text just a little (around 76%) so it wouldn't stand out so much.
Step Ten
Merge your layers and you're done! :D
You'll want to play around with the opacity on your layers until you're satisfied.
I use different levels for different pictures, so a lot will depend on the base you choose.
Please let me know if this was useful - I'd love to see what you make with it! :D