Possible parameters:

Parameter Name(s)DescriptionRequired
setSetAlias of requested SetAlias of Set to render
tText to personalizeYes
pwWidth in pixels of the resulting imageNot transmitting this value creates the image in original width
cJPEG Compression 20(worst) - 100(best)No
wtWatermark Type (0=None, 1=DirectSmile, 2=GenericNo
aniframeIf target is animation [aniframe=n] points the frame index [n] to renderNo
aniformatDefines the output format of the resulting animations, posible values: gif,aviNo
uAuthentication user nameProvide either Username, Password combination or AuthenticationCode
pAuthentication user nameProvide either Username, Password combination or AuthenticationCode
acAuthenticationCodeProvide either Username, Password combination or AuthenticationCode
return=urlReturn modespecify if you like to receive a url instead of a streamed image back

Please check documentation for instructions in detail.