Create your own timer, and attach it to the scene that is doing the image presentation. This is something that is very simple to do.
float delay = 3;
public Update()
{
delay -= Time.deltaTime;
if (delay <= 0)
LoadLevel("NextLevelToLoad");
}
EDIT
Apparently mobile runs the Update() of the first loaded scene while the splash is running? I haven't personally confirmed this, but it is plausible.
If that is the case, possibly try tapping into OnPreRender to initiate your timer.
Code would be:
float delay = 3;
bool timerEnabled;
public Update()
{
if (timerEnabled)
{
delay -= Time.deltaTime;
if (delay <= 0)
LoadLevel("NextLevelToLoad");
}
}
void OnPreRender()
{
timerEnabled = true;
}