Use the online graphreader tool to extract values from graph images - it only takes a few easy steps.
1) Select a png, jpg or gif image and press 'Go'. 2) Resize blue rectangle to set ruler for axis scaling. Set values for x- and y-axis scaling accordingly. 3) Double-click to insert curve fix-points. Right-click to delete points (on tablet long touch). 4) Click 'Generate curve' to sample curve. Use controls below to redraw output. 5) Scroll down for more options and to see generated CSV data.