Just reading through a trade journal here on bp and the poster posted huge charts…so this thread is just a test to see what the optimum size is…
800x1000
800x1500
365x238
600x800
600x600
1500x1500
I have to admit that it it a lots of lines - have you ever consider eye doctor ? 
800x800 and 800x1000 appear to be good sizes.
Although black backgrounds are very sexy, and very colourful, they do not give as good a resolution as white backgrounds.
Black is also very draining on the eyes.
Green, purple, red, orange backgrounds should be avoided.
They tend to hide similar colours.
The candles need fine black borders.
Black wicks on the candles are clearer than coloured ones.
The borders are then also easier to see.
800x600 thumbed view which then can be enlarged to original resolution is good.
Keep in mind the average user resolution is probably 1024x768 so going larger than that is a nuisance.
This is one annoyance I find about babypips…the size they let you upload is apparently only 700 x 700, and when you click on the thumbnail, it’s waaaay too small they don’t have a zoom function for it like some other forums do. I’ve mentioned this in their “give feedback” many times. I realize the storage space needed to host the pics is a major factor in what they can alot, but it’s not up to standard compared to what the other major forums allow.
So then the only other option is to host the pics on another website and imbed a link to display it right in the post. That can result in a better sized pic without having to go to a second window, however in doing so some waaay exceed the boundaries of the web page and one has to scroll vertically and horizontally to view the whole pic…still annoying…not too mention it distorts the other posts on the page.
Yep I agree…on all points.