vidma

If you happen to rely on VirtualBox and need to easily handle VDI files, a software utility such as vidma could prove a handy companion since it is capable of adjusting their size without requiring considerable effort on your part.
Before anything else, it need be mentioned that vidma packs no GUI since it is a command-line application helping you manipulate virtual disk images.
To understand the context, it is worth noting that VDI is a disk image format specific to the aforementioned desktop virtualization program that can emulate an operating system, with vidma being capable of resizing these virtual images in no time.
All that’s required for you to run the program is indicate the VDI file you want to adjust along with its new size in megabytes. Note that you can either replace your original image disk file or simply create a new one, which is actually the recommended option since it minimizes the risk of data loss in case the task is not carried out as expected.
However, if you do not indicate otherwise, the new image will overwrite the original, so extra attention is recommended.
Once you have taken this step, you are provided with several details about the operation you want to perform, with the input and output file size being shown along with the required and available free space on the volume.
After you approve the changes you want the image to undergo, the program keeps you updated with each stage of the process so that you know when your new VDI file can be accessed.