How can I mount an encrypted disk image so that it is read-write?

I have created an encrypted disk image containing a folder whose contents that I want to keep secure, using the disk utility app. I am able to mount this either by clicking on the image or by using the command line, however in either case, the mounted drive is read-only. I have tried various options including adding the -o read-write option to the command line mount command, however nothing seems to work. I am running under OS X 10.14.5.

Solution 1:

When the Disk Image is created is the time to decide if the image will be compressed (default) read/write or other options. The option you should have now is to Disk Utility:Images:Convert and choose the image you want to be read/write and choose Convert