Nice to see another Serif website. I found that the fishcam didn't work, but all else looked fine. A bit of a busy site for my tastes, but that's just me. Other than that, it looks like a nice bit of work for WebPlus.
The fish cam is an offsite link that seems to have occasional problems ... I agree it is a bit busy, but then again this is for a RV Park at the beach. Suave and sophisticated would seem a bit out of place (except in Santa Barbara!) <sigh>
I saved that 140 KB image to my hard drive, then using irfanview, immediately resaved it without modifying it as a JPG using the standard 80% compression, and it looks just as fine as can be. And now as a JPG its 20 KB.
Let's see, that's 7 times smaller in bytes than the PNG image there now. Dial up users will love the JPG.
If you go to WP9's Files/site-properties, you can change the default made images from PNG to JPG. If you do, change the compression from the 10 that's default, to 5. 10 makes images a bit ragged while at 5 the images come out nice.
That image file of yours ended up with a WP9 filename. That means WP9 took it over once you imported it and placed it on a page. If you import in the JPG it should keep the original format ---- however, if you mess with the image while inside of WP9, like add contrast or change brightness, or shrink it some or grow it some, or even overlap it over part of another image and a text box, WP9 might decide to take-over ownership and so your JPG will once again become a PNG file if you keep PNGs as WP9's default image type.