I made it in my iPad using pixelable and when i first uploaded, the iPad saves it as an image so the image is automatically resized. Then I mailed to to my pc, opened in gimp, resized it and then exported it as png and then reuploaded it. I guess there is some mistake over there...

thnx for ur reply! Means a lot to me... working on to improving my pixel habits xD... yeh u were right, the lights look too scattered and the kite do look jaggery... 

Anyway thnx again... have a nice day..!

Hello and welcome! Be sure that everyone is worthy enough of participating in weekly challenges! This place is all about learning and progressing, challenges are motivational. Also you seem to have a great attitude about feedback: you'll do well here I'm sure =)

Here is a handy tool to check colors. As yahkehbu said, there are 1445 in this piece, likely accidentally. Possible reasons:
- uncontrolled resizing. You can't resize pixel art except by nearest-neighbor and integer factor (x2, x3 etc). And you cannot, ever, downsize pixel art. Your preview has been destroyed by the downsizing! Don't do that (usually pieces are sent for revision because of downsized previews), crop a part instead.
- piece was saved as jpeg at some point. Don't. Ever. Png or gif are good.
- some soft tool was used accidentally: brush instead of pencil, soft eraser, opacity not 100%, auto-anti-aliasing not turned off, etc. Check your tool settings! What software are you using?
- some filter was used such as sharpening. No. Don't!

There are artefacts in the image which hint at one or more of these possible causes.

Other than that, the piece is nice and has a good atmosphere. I love the far skyline!

There are too many isolated pixels, they look noisy. I suppose the bright pixels on the buildings are windows? They should be aligned, and less bright, they are too distracting.

Some lines and shapes could look cleaner, esp. the kite which is the focus of the piece: it should receive the most pixel-level attention. Pixel art is all about perfect placement of each single pixel! It can take minutes to try the best position for just one of them =)

Finally, I think it would be nice to have all colors in the blue-purplish range including the foreground, to unify the piece and make it feel even more nightly.
Or all blue except red kite, might work too.

Keep at it and have fun!

Oh no!  There are now 1445 colors?! Hopefully you can upload a clean version in time! Max 20 colors.

Glad that you are joining the weekly! On pixeljoint its best to upload the image at original size, since the gallery already provides users with zoom. Click the edit button and just re-upload a new (downsized) version. Also useful if you want put any critique you might get to use on the specific work :)

Best of luck!