@warox, those are cute trees.
If you are willing to pay, there’s a vibrant job offer forum on pixeljoint and pixelation. If you put out a serious offer, you are likely to get quite a bit of serious replies. Do size up a realistic budget first though.
If you are looking for placeholder sprite art to test your concept first, spriters-resource.com has a good library and search function
If you are looking for free art, there some sites like lostgarden.com out there.
I guess dropbox link is not working right?
Inkscape on iPad for vector drawing
opengameart.org for art or lostgarden.com for other art
Edit:whoops this is an old thread sorry