How many do you need? I don't know the answer, but just ran a quick test and had no issues adding 1000 frames... I suspect you could go alot higher, I just got bored of waiting for it to load all those images...
SetVirtualResolution(480, 320)
SetSyncRate(60, 1)
SetClearColor(0, 0, 0)
global Sprite
global j = 1
Sprite = CreateSprite(Sprite)
for i=1 TO 1000
AddSpriteAnimationFrame(Sprite, LoadImage("BackGround" + Str(j) + ".png"))
j = j + 1
if j=11
j = 1
endif
next i
do
if GetSpritePlaying(Sprite) = 0
PlaySprite(Sprite, 20, 1)
endif
Print(ScreenFPS())
Print(GetSpriteCurrentFrame(Sprite))
Sync()
loop
EDIT: Ok, so I'm at work and quickly realised that waiting for all those images to load was way more fun than working. I tried with 10,000 animation frames and it still works with no issues (on Windows). Is that enough?