Minecraft server querier that generates an image of online players
Maybe it will not increase the performance, but I have some general tips:
Use while loops instead of for-loops with break. It will make your code more readable.
I have rewritten the createImage function for you:

def createImage(players):
    # create a blank transparent image with the dimensions: 212x147px.
    baseImage = Image.new("RGBA", (212, 147))
    slotList = [(17, 17), (82, 17), (147, 17), (17, 82), (82, 82), (147, 82)]

    x = 0
    while x &lt; len(players) and x &lt; 6:
        face = Image.open(str(players[x]).lower() + "_face.png", 'r')
        baseImage.paste(face, slotList[x])
        x += 1
    baseImage.save("server1_online.png")


If you prefer for over while, you can use:

def createImage(players):
    # create a blank transparent image with the dimensions: 212x147px.
    baseImage = Image.new("RGBA", (212, 147))
    slotList = [(17, 17), (82, 17), (147, 17), (17, 82), (82, 82), (147, 82)]

    for slot, player in zip(slotList, players):
        face = Image.open(str(player).lower() + "_face.png", 'r')
        baseImage.paste(face, slot)
    baseImage.save("server1_online.png")


Read more about zip here

You need to close the files you open:

# If nothing changed, pass!
if nameList == oldNameList:
    print("same thing!")

# Else, if no-one is on, but the text file says people are on, empty the text file.
elif len(nameList) == 0 and len(oldNameList) &gt; 0:
    print("everyone left :'(")
    tempFile = open('server1_previous_players.txt', 'w')
    tempFile.write("")
    tempFile.close()
    createImage(nameList)

# Else, if at least 1 person is on, generate a new image accordingly.
elif len(nameList) &gt; 0:
    tempFile = open('server1_previous_players.txt', 'w')
    # write should be used instead of print
    tempFile.write('\n'.join(nameList))
    tempFile.close()
    createImage(nameList)


An if-statement can be used without an else, so if there is only pass in there you don't need it.

If you want to create an empty / transparent image when nobody is on, you can combine both elif-statements:

# If nothing changed, pass!
if nameList == oldNameList:
    print("same thing!")


# else generate image and write new player list to file
else:
    if len(nameList) == 0 and len(oldNameList) &gt; 0:
        print("everybody left")
    tempFile = open('server1_previous_players.txt', 'w')
    tempFile.write('\n'.join(nameList))  # writes "" for an empty player list
    tempFile.close()
    createImage(nameList)