Images may contain blemishes or artificial structures which come from the processing or directly from the sensors. These artifacts decrease the quality of the images and can lead to analysis and interpretation problems. We are interested in detecting these defects automatically. A visual analysis of such artifacts brings to the conclusion that they constitute a local modification of the complexity of the image. Therefore this paper will give a complexity based approach for the detection of these defects. This approach will distinguich two different methods: firstly the artifacts will be looked for respectively to given example, with a complexity comparison. This method will involve both direct and model based means. From the weaknesses of that method a second one will be deducted which will not be attached to the given examples and will take into consideration the local complexity context of the image. These methods will be applied in the domain of Earth Observation images.