Hi Jeannie!
The quality of the image is never changed but I think perhaps the image size you are using is too small.
For instance when you click on this image the quality is still high and you can read all of the text.

However, in some cases the platform reduces the file size of images when they are uploaded to a topic in order to 'optimize' them, this is to prevent loading times on the topic page from being affected if it judges the image to be to large of a file size. So by reducing the file size it may cause the image to lose some of its sharpness.
Could you send me some examples of images this has happened with to support@insided.com so I can look into this further? Cheers!