You could but we don't recommend it.
If you do please be aware it could appear blurry if you want larger stickers.
We recommend either sending us vector artwork or if you're sending bitmap artwork, to send us 300 DPI resolution at a 1:1 scale of the sticker you want. Either of these will ensure the best output.
We have smart methods of increasing the resolution of bitmap images, but there is no replacement for sending in high-resolution images or vector artwork.
To learn about how you can increase the quality of your artwork, see here.