An image transmission method applicable to a cloud terminal, comprising: acquiring a plurality of images captured by the image acquisition device, calculating a similarity between an i th captured image and an (i-1) th captured image, and storing the i th captured image into a cache in response to the calculated similarity not exceeding a preset threshold, the i being an integer no less than 2; acquiring N images captured by the image acquisition device and consecutively stored into the cache, N being an integer greater than 1; calculating similarities between the N images and a reference image, respectively, the reference image being a locally stored image that is transmitted to a cloud desktop last time; determining a minimum of the similarities between the N images and the reference image, and selecting an image corresponding to the minimum as the image to be transmitted; and transmitting the image to be transmitted to the cloud desktop; wherein calculating a similarity between an i th captured image and an (i-1) th captured image comprises: dividing the i th captured image into a number of small blocks, comparing grey level and/or brightness and/or contrast of each small block of the i th captured image to the grey level and/or brightness and/or contrast of each corresponding small block of the (i-1) th captured image, and calculating a change value of the grey level and/or brightness and/or contrast; and wherein calculating similarities between the N images and a reference image comprises: dividing each of the N images and the reference image into a number of small blocks, comparing grey level and/or brightness and/or contrast of each small block of the N images to the grey level and/or brightness and/or contrast of each corresponding small block of the reference image, and calculating a change value of the grey level and/or brightness and/or contrast. acquiring a plurality of images captured by the image acquisition device, calculating a similarity between an i th captured image and an (i-1) th captured image, and storing the i th captured image into a cache in response to the calculated similarity not exceeding a preset threshold, the i being an integer no less than 2; acquiring N images captured by the image acquisition device and consecutively stored into the cache, N being an integer greater than 1; calculating similarities between the N images and a reference image, respectively, the reference image being a locally stored image that is transmitted to a cloud desktop last time; determining a minimum of the similarities between the N images and the reference image, and selecting an image corresponding to the minimum as the image to be transmitted; and transmitting the image to be transmitted to the cloud desktop; wherein calculating a similarity between an i th captured image and an (i-1) th captured image comprises: dividing the i th captured image into a number of small blocks, comparing grey level and/or brightness and/or contrast of each small block of the i th captured image to the grey level and/or brightness and/or contrast of each corresponding small block of the (i-1) th captured image, and calculating a change value of the grey level and/or brightness and/or contrast; and wherein calculating similarities between the N images and a reference image comprises: dividing each of the N images and the reference image into a number of small blocks, comparing grey level and/or brightness and/or contrast of each small block of the N images to the grey level and/or brightness and/or contrast of each corresponding small block of the reference image, and calculating a change value of the grey level and/or brightness and/or contrast.