ios - Loading multiple saved images in app slows it down -

i developing app user can save 13 screenshots , display them on single view thumbnails or full screen image.

let filename:string = self.stickerused + ".png" var arraypaths = nssearchpathfordirectoriesindomains(.documentdirectory, .userdomainmask, true)[0] nsstring var pngfilename = arraypaths.stringbyappendingpathcomponent(filename) uiimagepngrepresentation(screenshot).writetofile(pngfilename, atomically:true) nsuserdefaults.standarduserdefaults().setobject(filename, forkey: self.stickerused) nsuserdefaults.standarduserdefaults().synchronize() 

this above how save image , following how retrieve images. code first screenshot:

var defaultname:string = "sticker1.png" let path = nssearchpathfordirectoriesindomains(     .documentdirectory, .userdomainmask, true)[0] nsstring let filename = nsuserdefaults.standarduserdefaults()     .stringforkey("sticker1") ?? defaultname let imagepath = path.stringbyappendingpathcomponent(filename) let image = uiimage(contentsoffile: imagepath ) 

the problem displaying them in single view gets slow number of screenshot increases. app crashes after showing "received memory warning". new swift , app development. right way display these images in thumbnail without slowing down or crashing , saving image in full resolution.

the problem following code have images in full resolution:

let image = uiimage(contentsoffile: imagepath ) 

it better scale down , make thumbnail after loaded memory:

// line still same let image = uiimage(contentsoffile: imagepath )  // scale image down:  let newsize = ... // defined new size here                   // should idea match                    // size of uiimageview uigraphicsbeginimagecontext(newsize) image.drawinrect(cgrect(origin: cgpointzero, size: newsize)) image = uigraphicsgetimagefromcurrentimagecontext() uigraphicsendimagecontext() 

see more: link.