我正在尝试使用iconutil从iconset目录生成icns文件。如果图标集目录包含png格式的所需文件，则它可以正常工作。如果它包含jpg格式的所需文件，我会得到
/private/tmp/MyIcon.iconset:warning: No image found for point size: 16 at scale: 1.
/private/tmp/MyIcon.iconset:warning: No image found for point size: 16 at scale: 2.
/private/tmp/MyIcon.iconset:warning: No image found for point size: 32 at scale: 1.
/private/tmp/MyIcon.iconset:warning: No image found for point size: 32 at scale: 2.
/private/tmp/MyIcon.iconset:warning: No image found for point size: 128 at scale: 1.
/private/tmp/MyIcon.iconset:warning: No image found for point size: 128 at scale: 2.
/private/tmp/MyIcon.iconset:warning: No image found for point size: 256 at scale: 1.
/private/tmp/MyIcon.iconset:warning: No image found for point size: 256 at scale: 2.
/private/tmp/MyIcon.iconset:warning: No image found for point size: 512 at scale: 1.
/private/tmp/MyIcon.iconset:warning: No image found for point size: 512 at scale: 2.
/private/tmp/MyIcon.iconset:error: Invalid iconset, no resources found in iconset.
MyIcon.iconset:error: Failed to generate ICNS.
然而，目录中有这些图像
4190 21 Aug 16:31 icon_128x128.jpg
4958 21 Aug 16:31 icon_128x128@2x.jpg
3938 21 Aug 16:31 icon_16x16.jpg
3950 21 Aug 16:31 icon_16x16@2x.jpg
4958 21 Aug 16:31 icon_256x256.jpg
8030 21 Aug 16:31 icon_256x256@2x.jpg
3950 21 Aug 16:31 icon_32x32.jpg
3998 21 Aug 16:31 icon_32x32@2x.jpg
8030 21 Aug 16:31 icon_512x512.jpg
32606 21 Aug 16:31 icon_512x512@2x.jpg