[Sumatra PDF][1], though mainly used as a native PDF reader, [DJVU][2], and EPUB reader, also has the functionality to open [most image formats][3] and automatically refresh the viewer:

> PDF (.pdf) eBook formats: unencrypted EPUB (.epub) MOBI (.mobi)
>
> Fiction Wise (.fb2, .fb2z, .zfb2) .pdb (Palm DOC format) .tcr 
>
> Comic book files: .cbz, .cbr, .cbt, .cb7z DjVu (.djv, .djvu) 
>
> Microsoft Compiled HTML Html (.chm) XPS (.xps) 
>
> Images (.tga, .gif, .jpg, .j2k,> .png, .webp, .tiff)
> 
>  It doesn't lock the file if any other program is processing it.

Further usage documentation can be found [here][4].


  [1]: https://www.sumatrapdfreader.org/free-pdf-reader.html
  [2]: https://en.wikipedia.org/wiki/DjVu
  [3]: https://www.sumatrapdfreader.org/docs/Supported-document-formats-0b6aad81599446829531ee215f11f2ea.html
  [4]: https://www.sumatrapdfreader.org/manual.html