In this paper, the first of a two-part series, a high- compression image transformation (called EBLAST for Enhanced Blurring, Local Averaging, and Thresholding) is presented that facilitates image transmission along low-bandwidth channels such as acoustic modems, and exhibits low mean- squared error with spatially uniform reconstruction error. Although initially applied to tactical communication problems, this innovative transform Blurring, Local Averaging, and Thresholding), can be used in commercial applications such as videotelephony. EBLAST's compression ratio (CR), which usually ranges from 100:1 to as high as 250:1 on underwater imagery, can in some cases be increased by follow-on Huffman encoding to yield CR approximating 300:1 with no additional information loss. Additionally, in previous work the authors showed that restriction of the source image to typical targets of interest, followed by compression, could increase CR to 20,000:1 or greater. In such cases, background information is characterized, then discarded prior to compression. In the decompression step, the background is approximately reconstructed from statistical parameters, which can provide verisimilitude for human target cueing applications.