Those are the original images themselves lets look at post 2 on main page for example
RC pilot har styr på det
Original image uploaded 320px × 180px
[The image dimension cannot be scaled to 200x200 due to the original size as the height is 180px.......
Result Thumb Scaled (scaled to 200px × 113px)
As you can see if you want 200x200 your original image must be 200px high to begin with.
The width does not matter as long as it is also over 200px it will then rescale the original to 200x200 and you will not have that issue hope that helps.
As i said before also the post having no text in them also affects this smushing together of the post.