I agree hoof when our Pixels go into vector programs, and page lay-out programs image resolution needs consistancy, acording to out put requirements ( lines per inch / half-tone screen resolution in print production.) but.. i'm on of those people who save vector files as EPS. save Photoshop files as Tiff ( with Clipping paths sometimes) then I go into the page layout and insert the images into the boxes.. then insert the text into text boxes( needing at least three applications) it would save some time to just make an illustrator file, and imput the pictures there, with the correct imposistion... I've forgoten why some suggest not do it that way. we are the juglers in this digital circus aren't we... (?) ---------- one of the options is not vewing a document at 100 % because basicly your looking at a your image at he same resolution as your monitor, there is the option of * view - print size * with your Ruler's turned on you can faily quickly understand it's dimentions (in inches ) a image that is not re-sampled for example a 100 dpi , 12x 12 inch image - increased to 300 dpi will print out to be 4x4 inches , I think the file size in MB, will basicly be the same. --- to answer the initial question.. in photoshop - it's the amount of pixels. for example a 100 dpi 12"x12" document will have 1,440,000 pixels. a 300 dpi 12"x12" document will have 12,960,000 pixels. guess which takes up more memory? it uses up ram to display the pixels and to diplay the brush... and other things. this is basicly why it's slowing down the painting / rendering process