FileUnitTestCase::testImageDimensions in modules/file/tests/file.test
Tests storing image height and width as file metadata.
file_validate_image_orientation in includes/file.inc
Check for EXIF orientation data and rotate file if needed.
file_validate_image_resolution in includes/file.inc
Verifies that image dimensions are within the specified maximum and minimum.
image_style_create_derivative in modules/image/image.module
Creates a new image derivative based on an image style.
ImageToolkitGdTestCase::testManipulations in modules/simpletest/tests/image.test
Since PHP can't visually check that our images have been manipulated properly, build a list of expected color values for each of the corners and the expected height and widths for the final images.
ImageToolkitUnitTest::testSave in modules/simpletest/tests/image.test
Test the image_save() function.