Nearmap supports PNG and JPEG through the WMS service. Each GIS application will have a means of specifying the image format or image encoding. Most GIS applications have PNG as the default image format for WMS requests.
We recommend that you instead set the image format to JPEG when you set up a WMS connection to Nearmap . Setting JPEG as the image format will result a substantial improvement in performance due to much less data being downloaded, with only a small reduction in quality compared to PNG. We strongly recommend using JPEG as it is a more effective compression format; images should download more quickly and use less data. It comes at a very slight cost to image quality, but the difference is negligible.
When to Use PNG
When loading raster maps, such as Nearmap imagery, PNG has several advantages and several disadvantages. PNG has a transparency channel, which means you can overlay Nearmap imagery on top of another basemap (for example a worldwide satellite layer or a roadmap). This works best when at small scale, for example when using a city or statewide extent. Note that PNG imagery is not compressed as much as JPEG and it will take longer to download.