Hello!
I'm really new in MIT App Inventor and in programming in general, actually. Currently, I'm making an app for a board game I've designed about biological evolution for high school students. In a few words, the game is like a Pokemon inspired board game in which players will play with 1 of 72 possible playable cards (I've already designed the 72 cards), which will be radomly assigned in the beginning for each player. There is the option of doing this analogically, but one app will do it more efficiently that a bunch of dices. I solved the random assignation of a card for each player, but now I'd want to access an image in a folder from the app. I don't want to upload the images from the app, but the folder to be previously uploaded to a sort of database where the app can access the images in any time, if possible. I've read that there are databases associated with App Inventor, but I don't know how to upload this folder (with 72 images) to some database without uploading one by one the images from the App Inventor. Thank you all in advance and sorry for my English! 
You Can Use Firebase Storage
This is the Firebase Storage Extension :
There Is Also Cloudinary For Saving Files, Img, Video Etc.
You could also use:
Your own CloudDB / Redis server
Your own php server
Google Drive
AI2 has an easy drag and drop facility you can use to avoid online hassles.
Just be sure to reduce the file sizes and pixel counts before the upload.
Sample video:
If the images are optimised for Android (= small file size), why wouldn't you want them stored with the App? It's relatively secure, the App can load them quickly and there is no Internet dependency.
I read all your comments and I'm very thankful. However, I hadn't enough time for really getting into how to upload and download the images through the extensions (I don't know if it's necessary to install something 
), so, at the end, I decided to put them all into the app. Nonetheless, I recently realized that the sizes were tooooo much bigger than I thought, so I will reduce them again (now following the link of ChrisWard -thanks!-), but they're 72 images (and like 5, more or less, for icons) and they're supposed to be as large as the screen wide (they can be at some smaller quality, nevertheless).
This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.
Should be fine Jaramango
You can reduce image size both dimensionally and the colour bits used. Even some photographs have relatively few unique colours, in which case they can go down to 16bits. Most image processing software reports the total number of unique colours so you can always make an informed decision.
For everything except the file for the App launch icon (which must be PNG), use Webp format.