I did like this
 
	 
 
	 
 
	 
 
	ht = 0 
	r,g,b = 200,200,200 
	local sx_, sy_ = guiGetScreenSize() 
	local sx, sy = sx_/1024, sy_/768
 
	addEventHandler("onClientRender", root, 
	function() 
	getElementHealth(ped) 
	DXDrawBorderedRectangle(322*sx, 686*sy, 379*sx/100*ht, 27*sy, tocolor(200, 0, 0, 200), false) --- DAMAGE 
	dxDrawImage(322*sx, 686*sy, 379*sx/100*75, 27*sy, "files/health.png", 0, 0, 0, tocolor(255, 255, 255, 30), false) 
	dxDrawRectangle(322*sx, 686*sy, 379*sx/100*getElementHealth(localPlayer), 27*sy, tocolor(r,g,b, 255), false) 
	if getElementHealth(localPlayer) <= 30 then 
	r,g,b = 200,0,0 
	else 
	r,g,b = 200,200,200 
	end 
	end 
	end 
	)