try this, it looks ok in win & html5
maybe its the size or the position which cause the lines in grid or alpha or any image/sprite settings commands.
rem
rem AGK Application 2017.01.09
rem MR
SetWindowAllowResize(1)
SetWindowSize(1280,720,0)
SetVirtualResolution(100,100)
//16x11
img1= LoadImage("block.png")
img2= LoadImage("tree.png")
spr1=Createsprite(img1)
spr2=CreateSprite(img2)
SetSpriteSize(spr1,-1,7)
SetSpriteSize(spr2,-1,7)
local x as float
local y as float
local x1 as float
local y1 as float
local w as float
local h as float
w=GetSpriteWidth(spr1)
h=GetSpriteHeight(spr1)
for x = 1 to 16
for y = 1 to 11
x1=w+(x-1)*w
y1=h*2+(y-1)*h
spr=CloneSprite(spr1)
SetSpritePosition(spr,x1,y1)
if Random2(0,1)= 1
spr=CloneSprite(spr2)
SetSpritePosition(spr,x1,y1)
endif
next
next
Do
//Html5 have no End
sync()
Loop
end
AGK (Steam) V2017.01.09 : Windows 10 Pro 64 Bit : AMD (16.12.1) Radeon R7 265 : Mac mini OS Sierra (10.12.2)