Image photographing method and device and terminal device

The invention provides an image photographing method and device and a terminal device. The method is applied to the terminal device. The terminal device is equipped with a master photographing module and a secondary photographing module. The method comprises the steps of controlling n adjacent pixels corresponding to the same light filter unit in a secondary image sensor to be located in different exposures according to a preset strategy; obtaining a first image and a second image of a photographed object through a master photographing module and the secondary photographing module; splitting the second image, thereby obtaining a third image, wherein the third image and the first image have the same number of pixels; and synthesizing the third image and the first image, thereby obtaining a high-dynamic range image of the photographed object. The two photographing modules are employed; one is used for carrying out normal photographing; the other one is used for obtaining the image with different exposures; then the two images are synthesized to obtain the HDR (High-Dynamic Range) image; the photographing time of the HDR image is shortened; the image photographing effect is improved; and the user experience is improved.