Cant upload images for poster.

Hi there, Hoping someone can help me.... loving this game! cant wait for more updates in the meantime as the title suggests i cant upload ANY images to use for a poster...
when i left click the mouse i search for an image (tried 4 different ones) then clicking "select image" screen goes dark with the words " PREPARING IMAGE (image name)" and thats it... nothing else happens......left it for 5 mins no change... only way to come out of that screen is press escape... I did check Red51 troubleshooting guide but didnt find anything on this..... any ideas or help would be much appreciated ... thanks

Thanks for the reply keep up the good work