Image I/O Plugins provided as part of an extension installed into the JDK don't seem to be picked in an applet environment.

A simple test case demonstrating this is attached.

To run, first JAI Image I/O tools needs to be installed. This can be downloaded from here

http://java.sun.com/developer/earlyAccess/jai_imageio/index.html

Installation instructions are outlined here

http://java.sun.com/developer/earlyAccess/jai_imageio/INSTALL-jai_imageio.html

Look under "Installation in a JRE" heading

Once you have this installed, to try this out in an application environment, simply run "java IIOAppletTest" and you should see this output

Reader names:
tif tiff JPEG-LOSSLESS jfif wbmp jpeg-lossless jpeg2000 gif WBMP BMP bmp jpeg-ls JPEG 2000 TIF JPEG2000 JPG PNG JPEG raw PNM jpeg RAW jpeg 2000 pnm TIFF JPEG-LS png jpg JFIF
Reader Mime Types:
image/x-portable-graymap image/jpeg image/x-portable-pixmap image/x-portable-anymap image/png image/x-png image/jpeg2000 image/tiff image/vnd.wap.wbmp image/bmp image/x-portable-bitmap image/gif

Running as an applet, "appletviewer IIOAppletTest.html" gives the following output, not reporting any of the extension reader/writer plugins

Reader names:
BMP bmp jpeg wbmp gif png JPG jpg WBMP JPEG
Reader Mime Types:
image/png image/jpeg image/x-png image/vnd.wap.wbmp image/bmp image/gif Reader names:
BMP bmp jpeg wbmp gif png JPG jpg WBMP JPEG
Reader Mime Types:
image/png image/jpeg image/x-png image/vnd.wap.wbmp image/bmp image/gif

This seems to indicate that plugins from installed extensions are not picked up in an applet environment.