Add your repository

git config --file=.lfsconfig lfs.url https://lfs.ltbl.fr/lfs/<your-repo-name>
git config lfs.https://lfs.ltbl.fr/lfs/<your-repo-name>.locksverify true
git lfs install

Filter your big files to use LFS Warehouse

git lfs track "*.psd"

Use your Bitbucket app password and start commit with Git LFS.
LFS Warehouse requires Account > Read and Workspace membership > Read on your app password.