You can nab GIMP from here :
Download GIMP (NOTE : This is the portable version, and does not actually install on your computer. So, if you do not like the program, you can easily remove it by deleting the folder it was extracted to.)
Just run GIMP, File > Open 'Fire1.PNG', choose the rectangle selection tool (top left on the floating toolbar), click and drag to select the area you want, Edit > Copy, New > Create > From Clipboard, File > Export > Select PNG [Drop-Down List] > Export ... you're finished!