I played with this a little with a test .dmg file similar to yours. There may be a problem with Disk Utility's Resize function, but you can work around it.
Use the best PDF compressor. Adobe invented the PDF format. Try the highest quality compress PDF online tool for free, and see how easy it is to reduce the file size of your large PDF files. Jun 03, 2019 Click the radio button for the level of compression you want to use, ranging from HF (Maximum image size), (HD 330 PPI) to Email (96 PPI). The lower the PPI, the more you will lower the file size of your Word document which will also decrease the image quality of the picture as well.
Resizing the .dmg image file and resizing its contained partition are separate procedures. You can see them both if you click on the little triangle in Disk Utility's Resize window:
.
.
After doing this, you see the following. The button to resize both the image and the partition is selected by default, which is what you want:
.
.
However after clicking the Resize button, my result was the same as yours - only the .dmg file was resized, not the contained partition.
To try to fix this, I did the following. Mount the image by double-clicking the .dmg file, select the .dmg file (upper icon) in the left pane of disk utility, and click the Partition tab. I was then able to pull down the lower-right corner of the partition graphic to fill the entire space.
.
This increased the size of the partition to the same size as the image file. I then clicked Apply.
How To Reduce Dmg File Size Chart
When I later checked the mounted partition in Get Info, it reported the new larger size of 5GB.
Reduce Dmg File Size
Mar 18, 2012 4:33 AM