1. A tactile feedback method for an electronic device, comprising: inputting an original image; converting the original image to a binary image, the binary image comprising a first grayscale value and a second grayscale value; converting the original image to a grayscale image, the grayscale image at least comprising a third grayscale value between the first grayscale value and the second grayscale value; generating an index map according to the binary image and the grayscale image, the index map comprising a plurality of index values indicative of different strengths for tactile feedback; detecting a touch input on a touch panel of the electronic device when the original image is displayed on a display panel; and driving a tactile activation unit of the electronic device to generate tactile feedback according to the index map in response to the detected touch input.