Well I can make a few comments right away, all of which are intended to be constructive. Personally, me and most regular mappers prefer to have pixel-perfect maps, so my comments are mostly aimed in that direction.
1) The map should not be resized unless it's absolutely necessary (like if it was so large that nobody could open the map with any program). In this case, it's hard to make out any details on the map, and although I don't really find the graphics attractive, they really should be presented in the best possible manner. From what little I've been able to calculate, the full-size map should be four times as big in every direction.
2) The map should be saved in a lossless format, again unless absolutely necessary. Saving as a JPG means that there will inevitably be a loss of quality in the image, and the smaller the file size, the worse the image will be. And once it's been saved as a JPG, there's no going back; the quality is gone forever. I really hope you kept a lossless version of it in another format. PNG (in my opinion) represent the best file size with no loss of quality, and can even be optimized to be smaller with dedicated programs like PNGGauntlet and PNGOut.
As for embedding the image directly in your post, by clicking on "Additional Options" on the Post Reply page, you can attach up to 4 images per post with a maximum file size of 1 Mb in total. Hopefully, this will help you make your map look as good as possible, and feel free to ask for more help if you need it.
