welcome to this wonderful community.
Not sure if I got your question right - you can pick up multiple pics at one time and attach them to a card. No problem!
When you wanna share a link to a folder (cause attention according to your account the Upload size is limited - a link may be the better choice) you can also use attachments and just insert the link and give it a proper name. I made good experiences using this in cards cause Trello is not for managing files. When your files change and you uploaded them you have to change them on the card, too.
Hope this could help you - feel free to ask for more help!
Hello Community! My name is Brittany Joiner and I am a Trello enthusiast and Atlassian Community Leader. I'll be sharing with you a series of videos with my top tips on how to best use Trello...
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