To send saved pictures from your gallery to other people just by swiping to the right on another individual name, but there is no possibility of uploading them on your story. Using the special apps from Apple Store or Google Play like Swift Pic, Photosaver or Snap Up, you can upload your images to Snapchat.
To put a picture from your camera roll on your Snapchat story, Open the Photos app and find the photo you want to share. Tap on the photo and then on the Share icon at the bottom of the screen. Scroll to the right on the row of icons and tap on More. Toggle Snapchat On and if you want to, move it higher on the list.
Note: If you want to send a picture from your camera roll on Snapchat, Select a pic from your Camera Roll and click the “Share” button at the bottom-left of your screen. Swipe through the icons and tap the “More” dots. Choose Snapchat. This loads the app so you can doodle on the image and add a caption.
But in this article, i will show you How to Upload Pictures to Snapchat Story use App for iOS. Why use app? because you can instant access and simple to use on Snapchat. Let’s follow steps in below for your iOS Device like Apple, iPhone, iPad and iPod Touch.
How to Upload Pictures to Snapchat Story for iOS

Upload & Roll (Camera pic and save for Snapchat)
Upload your images or videos saved on your camera roll to Snapchat. Apply filters, write messages, enhance images, draw and much more before sending your image to your Snapchat friends.
Download
Simply follow this easy steps:
1. Open CameraSnap and login with your Snapchat credentials.
2. Select the image/video you want to upload to Snapchat. Apply filters, drawings, or enhance the look of your images.
3. Choose which friends will receive the Snap. Hit send.