When Ponga pictures open, the default zoom level is affected by image size and the available canvas area. The objective is first to bring the image to 100% resolution and second to fit to the canvas.
The viewport is the zoomable area in a Ponga picture. In your browser that would be affected by the size of your browser window. In an embed it is affected by the defined size of the embed. Use pixels to define the vertical and horizontal size of your image and your viewport in an embed.
If your original image is just 120x90 pixels, it will appear very small in a browser window that had a viewport for the Ponga picture of 1200x900, for example. A high resolution image of 3600x2700 in that same browser window, however would appear of quite high resolution and fit nicely in the view port.
The simple rule to remember is that if the image is smaller than the viewport, then the image will adjust to 100% resolution and full size, if the image is larger than the viewport then the zoom level will zoom out on the image until it fits the view port. Ponga supports six levels of zoom.
Generally, the higher the resolution the original image, the better the viewer experience. So, to have room to zoom, bigger is better. Ponga currently supports a maximum file size of 30MB in JPG or PNG format. If you have any questions, feel free to reach out.