Every once in a blue moon, you'll run into a problem with your Drupal site where the solution involves patching core. Start by making sure that you have a safe place to apply your patch. This would be a 'dev' copy of the website, either running locally on your own computer, or in a development environment on the same server (or one that's identical) to your live site. *Never* apply patches directly to your live website - *especially* core patches!!!
1) Start from the root of your Drupal site.
3) Download the patch file from drupal.org
[.../drupal-7] > wget http://drupal.org/files/606598-core7-port-imagestyles-175.patch
If you don't have wget on your computer (with a mac you will need to install Xcode) then you can do the same thing with curl, as follows
[.../drupal-7] > curl -O http://drupal.org/files/606598-core7-port-imagestyles-175.patch
4) apply the patch
[.../drupal-7] > patch -p1 < 606598-core7-port-imagestyles-175.patch
If everything goes well, you'll see the files that are patched:
[.../drupal-7/sites/all/modules/contrib/panels] > patching file modules/image/image.admin.inc [.../drupal-7] > patching file modules/image/image.api.php [.../drupal-7] > patching file modules/image/image.install [.../drupal-7] > Hunk #2 succeeded at 454 (offset -1 lines). [.../drupal-7] > patching file modules/image/image.module [.../drupal-7] > Hunk #1 succeeded at 347 (offset 5 lines). ... etc [.../drupal-7] > patching file modules/image/image.test [.../drupal-7] > Hunk #2 succeeded at 462 (offset 56 lines). ... etc
5) Clear your caches, and go test your new fix/feature!