FileUnitTestCase::testImageDimensions in core/modules/file/tests/file.test

Tests storing image height and width as file metadata.

file_validate_image_orientation in core/includes/file.inc

Check for EXIF orientation data and rotate file if needed.

file_validate_image_resolution in core/includes/file.inc

Verifies that image dimensions are within the specified maximum and minimum.

ImageToolkitGdTestCase::testManipulations in core/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 core/modules/simpletest/tests/image.test

Test the image_save() function.

image_style_create_derivative in core/modules/image/image.module

Creates a new image derivative based on an image style.