When I upload my pics they are in very Bad Quality, why ???

Looks like you reduce the quality too much. Your castle picture is only about 60KB.
Train 118KB, springboard 113KB, pisa tower 114KB.

All images are resized and recompressed for viewing on the main entry page, however, if you click on your image on the entry page then you will see the full quality version that you uploaded.

I cant upload any images' , it gives me an error everytime! But when I set the Quality to low in ps then i can upload!

Photoshop is not known to make the most optimized jpg's.
To squeeze your image into the 125KB restriction you can:

a) make it smaller - minimum size would be 600px x 350px

b) when saving to JPG in Photoshop turn off the color profile embedding. While using the quality slider, look at the bottom of the JPG options window for the estimated file size.

or

c) save your image in a lossless format (TIFF) and use a different program to convert to JPG. I have been using XNview, which makes jpg's of the same quality about half the size

Use the save for web option. Just change the quality until it barely meets the qualifications.

you can set a given size for the image in save for web, then ps will calculate the quality ratio for your desired size.