Album View picture very slow

Hello together,
i have still one issue. album view on IOS app IPad is very slow.
Indexing is fast , but it take a long time to show the album picures.
Library size : 1800 Album, xxxxx tracks

album pics. I have one jpg in each folder which is named folder with an filesize of 1-4 mb.
the same picture is edited in each track
all meta data are edited in dbpoweramp
So what can i do to improve this, and what can Damien due to improve Audirvana?