ABSTRACT: Wireless Sensor Networks (WSN) have energy, bandwidth and computational constraints. Major source of energy consumption is transmission of image from source to sink and image processing at the nodes. The captured image at the source could be noisy, incomplete and redundant. Hence, images can be fused at the closer by neighbors and fused image is routed to the to sink provided they have correspondence to previously received image. Fused image free of redundancy, brings out complementary features and aids in further analysis. This paper brings out the energy and computational time aspects of fusion algorithms in WMSN for averaging, select maximum, PCA, DCT, DWT, SWT.