How would I go about sending a file message with multiple images?

[walter.rodriguez]

I’m pretty sure that this this the problem here. Your object source is not a valid File object.
Are you using a 3rd party component to get your images, correct?
If so, please check this response, it may help:

Send File issue

For Javascript use a valid FILE object. interface FileMessageParams { new(): FileMessageParams; file: File; fileUrl: string; fileName: string; fileSize: number; mimeType: string; data: string; customType: string; thumbnailSizes: Array<ThumbnailSize>; mentionType: 'users' | 'channel'; mentionedUserIds: Array<string>; mentionedUsers: Array<User>; metaArrays: Array<MessageMetaArray>; metaArrayKeys: Array<string>; // DEPRECATED pushNotif…