How do I edit a bitmap and maintain original resolution?

Should be a simple question. Using Designer Pro X I load a PNG file. I then do nothing except "save as" also in PNG format.

My expectation was I would get the same file. Instead it seems to have changed the resolution and now looks terrible.

An ordinary graphic program like paint.net or photoshop would save the same file back to disk.

There must be something I am failing to understand about Xara. How do I edit a bitmap and have it save back in its original resolution?

thanks

First thing to understand about DPX is that unlike paint.net or photoshop, it is not strictly a raster editor.
DPX is a vector illustration and graphics design application which can import bitmap data for use in you graphic designs.
Some basic bitmap manipulation tools and effects are provided to this end, but it's not a pixel pusher like paint.net or photoshop.
Think more 'CorelDraw'..

A simple bitmap only workflow:

File>>New>>Blank Photo

File>>Import>> find your .png

Manage your edits..

File>>Export PNG
Ensure the export settings are as you require.

IOW When you export your PNG, change the resolution from 96dpi to the images current resolution which you can see in the status bar in the lower left of the screen with the image selected.

By default, DPX exports at 96dpi, Windows screen resolution. So you need to change this setting for higher resolution images.

Thanks for the replies.

This seemed to work best when I set the DPI of the image being imported to 96DPI and then when I exported, setting the export resolution to the same as my original image.