function newSize(ImgTag,FitWidth,FitHeight) { var image = new Image(); image.src = ImgTag.src; if(image.width>0 && image.height>0){ if(image.width/image.height >= FitWidth/FitHeight){ if(image.width > FitWidth){ ImgTag.width = FitWidth; ImgTag.height = (image.height*FitWidth)/image.width; } else{ ImgTag.width = image.width; ImgTag.height = image.height; } } else{ if(image.height > FitHeight){ ImgTag.height = FitHeight; ImgTag.width = (image.width*FitHeight)/image.height; } else{ ImgTag.width = image.width; ImgTag.height = image.height; } } } }