component.ts

loadImages(): Promise<any> {
	let smart: PHFetchResult = PHAssetCollection.fetchAssetCollectionsWithTypeSubtypeOptions(
		PHAssetCollectionType.PHAssetCollectionTypeSmartAlbum,
		PHAssetCollectionSubtype.PHAssetCollectionSubtypeSmartAlbumScreenshots,
		null
	)

	let collection: PHAssetCollection = smart.firstObject
	if (!collection) {
		global.tnsconsole.error('!collection')
		return
	}
	if (!collection.isKindOfClass(PHAssetCollection)) {
		global.tnsconsole.error('!isKindOfClass(PHAssetCollection)')
		return
	}

	let assets: PHFetchResult = PHAsset.fetchAssetsInAssetCollectionOptions(collection, null)
	global.tnsconsole.log('assets.count', assets.count)
	if (assets.count == 0) {
		global.tnsconsole.error('assets.count == 0')
		return
	}

	PickerComponent.assetCount = assets.count - 1
	PickerComponent.assetIndex = PickerComponent.assetCount
	return this.pushAssets(assets).catch(function(err) {
		global.tnsconsole.error('err', err)
	})
}

pushAssets(assets: PHFetchResult): Promise<any> {
	return this.createPHImage(assets[PickerComponent.assetIndex]).then((src) => {
		this.images.push(src)
		PickerComponent.assetIndex--
		if (PickerComponent.assetIndex > PickerComponent.assetCount - 5) {
			return this.pushAssets(assets)
		}
	})
}

createPHImage(image: PHAsset): Promise<ImageSource> {
    return new Promise<ImageSource>(function(resolve, reject) {
        let resizeMode: PHImageRequestOptions = PHImageRequestOptions.new()
        resizeMode.resizeMode = PHImageRequestOptionsResizeMode.PHImageRequestOptionsResizeModeExact
        resizeMode.synchronous = false
        resizeMode.deliveryMode = PHImageRequestOptionsDeliveryMode.PHImageRequestOptionsDeliveryModeHighQualityFormat
        resizeMode.normalizedCropRect = CGRectMake(0, 0, 1, 1)

        PHImageManager.defaultManager().requestImageForAssetTargetSizeContentModeOptionsResultHandler(
            image,
            PHImageManagerMaximumSize,
            PHImageContentMode.PHImageContentModeAspectFill,
            resizeMode,
            function(img, data) {
                if (img) {
					let src = new ImageSource()
					src.setNativeSource(img)
					return resolve(src)
                } else {
					return reject(new Error('NULL IMAGE'))
                }
            }
        )
    })
}

template.html

<ListView [items]="images" (itemTap)="onItemTap($event)">
    <template let-item="item">
        <Image [imageSource]="item"></Image>
    </template>
</ListView>