My MousePlanet article today is a 135-image photo tour of “HalloweenTime” at the Disneyland Resort. That many photos would have been way too many for a traditional album format, so (since my photos are all on PicasaWeb anyway) I used the PicasaWeb embedded slideshow player. Unfortunately, it has some design issues that bother me: text (caption) color, size and background; speeding by the pictures way too quickly (3 seconds!) and a Picasa logo in the bottom right corner.

A bit of Googling found this blog post at Mat.Su which explains how to set the slideshow interval. The author mentions “taking a peek inside” the Flash file that actually powers the slideshow and so I thought that I might see what other hidden parameters I could find. Note, however, that I don’t know the first thing about Flex or ActionScript except in that it seems to be pretty similar to other C-style languages.

I ran slideshow.swf through Trillix Flash Decompiler and searched through the script code for variables which can be specified via the embed URL. It seems that these are part of a _root array. Some of them are understandable, others are not. Here’s what I found:

host – should always be picasaweb.google.com
port – presumably a TCP port
scalemax – unknown
interval – as described in the linked blog post above
gp – setting it to anything disables the display of the PicasaWeb username and icon, though the user icon is still shown
attachMovie – seems to call a function, but is part of the _root array so included in this list
getNextHighestDepth – seems to call a function, but is part of the _root array so included in this list
feed – the actual PicasaWeb album being displayed in the slideshow, URL-encoded
font – looks like it should control the caption text size, but in experimenting couldn’t make it do anything
text – RGB for caption text
textBackground – RGB for caption background
textAlpha – I think it’s a percentage value, controls the transparency for the caption background
captions – boolean, display captions or don’t
noautoplay – boolean, autoplay or don’t
RGB – frame around the slideshow

Hope this helps someone. I’d love to know what some of those other parameters do.