were there any coins bearing the image of the king?
No. Coins carried his name.
Offa of Mercia
The new pennies almost invariably carried both Offa's name and the name of the moneyer from whose mint the coins came.
who is offa of mercia? King of Mercia, a kingdom of Anglo-Saxon England
wiki:11603099
Offa of Mercia [SEP] Coinage
The new pennies almost invariably carried both Offa's name and the name of the moneyer from whose mint the coins came. The reform in the coinage appears to have extended beyond Offa's own mints: the kings of East Anglia, Kent and Wessex all produced coins of the new heavier weight in this period. Some coins from Offa's reign bear the names of the archbishops of Canterbury, Jænberht and, after 792, Æthelheard. Jænberht's coins all belong to the light coinage, rather than the later medium coinage. There is also evidence that coins were issued by Eadberht, who was Bishop of London in the 780s and possibly before.