When you produce graphics they should be set at 72 dpi (or as close as your scanner or drawing software allows) since most monitors display at 72 dpi. Many web-browsers will "blow-up" images with higher resolutions until they approximate 72 dpi. For example, a 2 X 2 inch image with a resolution of 150 dpi will be about 4 X 4 inches on a 72 dpi monitor.
visres.cdr exported to visres.gif at 75 dpi (2K)
visres.cdr exported to visres.gif at 150 dpi (4K)