Rebecca-Jayne, if you don't want avatars to be rounded on User Profile page, you will need to customize your CSS code.
Go to Admin Area > Appearance > Customize > CSS tab and add following code:
div#avatar_console_image {border-radius:0 !important; -webkit-border-radius: 0 !important;}
To make the avatar's white background transparent, add this code:
.profile-BASE_CMP_UserAvatarWidget .ow_box_empty { background-color: transparent; }
.ow_avatar_console{background: transparent; border-width: 0px!important; }
If you have further questions about on how to modify theme appearance by using CSS custom code modification, it would be better to create topic within Development section in Themes forum.