When an organisational logo is uploaded by an org admin the logo is initially resized to be 75px tall by Dragonfly.
When the logo is later displayed to a user it is resized again to be 100px tall, resulting in a blurry image.
Both sizes of logo can be viewed on the 'Organisation details' page - note that the logo at the top appears blurry:

I tested by uploading a logo which was already 100px tall - the resulting 100px tall image displayed to the user is of noticeably lower quality than the source image:
