5.3.0 (2018-10-01)

API Changes

Image size

If you attempt to set the size of an image directly, e.g. im.size = (100, 100), you will now receive an AttributeError. This is not about removing existing functionality, but instead about raising an explicit error to prevent later consequences. The resize method is the correct way to change an image’s size.

The exceptions to this are:

  • The ICO and ICNS image formats, which use im.size = (100, 100) to select a subimage.

  • The TIFF image format, which now has a DeprecationWarning for this action, as direct image size setting was previously necessary to work around an issue with tile extents.

API Additions

Added line width parameter to rectangle and ellipse-based shapes

An optional line width parameter has been added to ImageDraw.Draw.arc, chord, ellipse, pieslice and rectangle.

Curved joints for line sequences

ImageDraw.Draw.line draws a line, or lines, between points. Previously, when multiple points are given, for a larger width, the joints between these lines looked unsightly. There is now an additional optional argument, joint, defaulting to None. When it is set to curved, the joints between the lines will become rounded.


Previously ImageOps.colorize only supported two-color mapping with black and white arguments being mapped to 0 and 255 respectively. Now it supports three-color mapping with the optional mid parameter, and the positions for all three color arguments can each be optionally specified (blackpoint, whitepoint and midpoint). For example, with all optional arguments:

ImageOps.colorize(im, black=(32, 37, 79), white='white', mid=(59, 101, 175),
                      blackpoint=15, whitepoint=240, midpoint=100)


While ImageOps.fit allows users to crop images to a requested aspect ratio and size, new method ImageOps.pad pads images to fill a requested aspect ratio and size, filling new space with a provided color and positioning the image within the new area through a centering argument.

Other Changes

Added support for reading tiled TIFF images through LibTIFF. Compressed TIFF images are now read through LibTIFF.

RGB WebP images are now read as RGB mode, rather than RGBX.