300903 2025-10-16 10:17:21 -0700 REGRESSION(293871@main): WeChat app allocates large sizes of memory for high resolution images on iOS 26 2025-10-17 10:51:59 -0700 1 1 1 Unclassified WebKit Images WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED https://bugs.webkit.org/show_bug.cgi?id=291765 InRadar P2 Normal --- 1 sabouhallawa sabouhallawa sabouhallawa webkit-bug-importer oldest_to_newest 2151704 0 sabouhallawa 2025-10-16 10:17:21 -0700 The change 293871@main removes setting the value for the key kCGImageSourceSubsampleFactor in the decoding options. This option is very useful when decoding a high resolution image which will be displayed on a much smaller rectangle. ImageIO decodes the image with a smaller rectangle in this case. This saves memory and CPU time. 2151705 1 webkit-bug-importer 2025-10-16 10:17:27 -0700 <rdar://problem/162787553> 2151716 2 sabouhallawa 2025-10-16 10:48:12 -0700 Pull request: https://github.com/WebKit/WebKit/pull/52489 2152042 3 sabouhallawa 2025-10-17 07:12:53 -0700 Here are other repro steps: 1. On macOS lunch mini-browser or Safari 2. Lunch Activity Monitor to monitor the WebKit allocated memory 3. Open https://upload.wikimedia.org/wikipedia/commons/e/ea/Van_Gogh_-_Starry_Night_-_Google_Art_Project.jpg Result: WebKit allocates about 3GB and it may eventually jetsam and crash Expected: WebKit allocates about 200-400 MB and it does not jetsam or crash Note: The size of this image = { 30000 x 23756 }. The memory for decoding this image for its natural size = 30000 x 23756 x 4 = 2.7 GB. But since the window size is much smaller than the natural size of the image, the image should not be decoded for its natural size. This is called image sub-sampling which was dropped by 293871@main. 2152129 4 ews-feeder 2025-10-17 10:51:57 -0700 Committed 301729@main (c4dc35645e7b): <https://commits.webkit.org/301729@main> Reviewed commits have been landed. Closing PR #52489 and removing active labels.