Question

Foursquare’s category icons returned all have a white background and a rounded border.
Is it possible to get those images with transparent backgrounds and/or with no border?
It would really save a few couple of hours.

Answer 1

I don’t think they’re officially available with transparent backgrounds, no. However, I wrote a bit of python a while ago that will download all the category icons, which you can find here and then a bit of imagemagick wizardry should allow you to replace the white background with transparent.

A quick python script to go through a directory of images and call imagemagick on each one to replace a white background with transparent (you might need to play with the fuzz factor to get acceptable results):

import os

current_dir = os.getcwd( )
files = os.listdir( current_dir )
for fname in files:
    if '.png' in fname:
        trans_name = fname[ :fname.rfind( '.' ) ] + '_transparent.png'
        os.system( 'convert %s -fuzz 15%% -transparent white %s' % ( fname, trans_name ) )

Then to crop the border, do the same, but the imagemagick command you want is -crop, so replace the last couple of lines in the script with:

cropped_name = fname[ :fname.rfind( '.' ) ] + '_cropped.png'
os.system( 'convert %s -crop 26x26+3+3 %s' % ( fname,cropped_name ) ) 

hope that all helps (and saves a couple of hours of work!)