The logo in IMST is not used for Self Service
Logos used in Self Service are stored in the
Ora10gAS_R3\Apache\Apache\htdocs\HLAppResources_xxxxx\release\images\Logos and Ora10gAS_R3\Apache\Apache\htdocs\HLAppResources_xxxxx\release\Themes\THEME_DKBlue\images\MainLogo.gif
directories
I presume that the only logo format we support is GIF, and my research suggests that only MainLogo.gif (from the theme directory) and PrintLogo.gif (from the directory above) are used.