Let me start by saying (and making this perfectly clear) this is not a theme issue. TotalPress does nothing to any images you upload and insert into your posts or pages. It does not process them in any shape, form or fashion.
I visited the link you posted above and it seems that you are inserting the small version of the image and it is being stretched to fill the necessary area. If you click this link you will see this is the image that you inserted into your post: https://addwit.org/wp-content/uploads/2018/07/About-Addwit-2-183×300.jpg
Notice at the end of that it says 183×300 – that’s the actual size that your inserting into your post. I suggest you read the WordPress Codex on “Inserting Images into Posts and Pages”, https://codex.wordpress.org/Inserting_Images_into_Posts_and_Pages.
After you read this, go back to the page that you linked to, edit it and select the full size option for the image.
Hope this helps.