Large files can cause problems. For example, students need to keep files under 100MB for Turnitin submissions. For staff, file sizes should be kept low to help students downloading Minerva files on their mobile devices - the larger the file, the longer it will take to download (and some students will have low data allowances).
Large images are often the problem. These can usually be reduced in size without affecting quality. Files can also be compressed. Various compression strategies are used to algorithmically reduce the total amount of space required to store or transmit a file.
IT clusters have Corel Photo Paint Pro which can be used to resize and compress images. Staff can also request this programme.
Photo quality images may be saved as JPEG format to achieve very high compression levels without losing too much quality. Corel Paint Shop Pro Photo includes a useful image optimisation wizard to enable to you compare compression levels and see how they affect the quality of your file.
From the Corel Paint Shop Pro menu:
There are ways to quickly compress images within Office programmes such as Word and PowerPoint.
We recommend you save audio files as MP3s for use in Minerva. The MP3 format is ubiquitous and well supported by various web browsers and operating systems. File size can be reduced by modifying the compression level - the higher the compression, the lower the quality of the resulting recording. There is inevitably a trade off between quality and file size.
A popular software for recording and editing sound authoring MP3s is Audacity. Audacity is also available in IT clusters and on the staff IT desktop.
This video shows how to compress a file by reducing it to 64 bit-rate in Audacity:
The Audacity Wiki has additional tips and detailed information.