1. A method for reduced transmission of an image stream captured in-vivo, the method comprising: performing processing in an autonomous in-vivo imaging device, the processing comprising: determining similarity between captured image data and image data previously transmitted in a communication channel, by comparing sub-samples of image pixels from the captured image data and the image data previously transmitted; determining a quality level of the communication channel; and if the captured image data is substantially similar to the image data previously transmitted, and if the quality level of the communication channel is above a pre-defined threshold value, reducing transmission of the captured image data.