QImageWriter supportedImageFormats only sometimes includes JPEG. Why?

[philw]

On some of our installations built with Qt 4.3.3, users are seeing the results of QImageWriter::supportedImageFormats to be only these items -- and this is a problem for us:

bmp Image (*.bmp)
png Image (*.png)
ppm Image (*.ppm)
xbm Image (*.xbm)
xpm Image (*.xpm)

On other installations, the following items are also shown:

jpeg Image (*.jpeg)
jpg Image (*.jpg)

Why might this be? And how can we make the JPEG options show up on all installations?

Thanks in advance,
Phil Weinstein, Boulder CO USA
http://cadswes.colorado.edu/

[wysota]

Probably because of this:
http://www.qtcentre.org/forum/faq.ph...missing_images

[philw]

Yes, absolutely right. Thank you. Here is the relevant part of that FAQ:

You probably didn't deploy image plugins with your application. You need to copy the contents of plugins/imageformats directory of your Qt installation to the imageformats subdirectory of the directory where you deployed the application binary.

For instance if you deployed the application to C:\Program Files\MyApp, you need to copy the plugins to C:\Program Files\MyApp\imageformats.

Imageformat plugins are libraries called "qjpeg", "qsvg", "qtiff", etc.