Can confirm that previous snippets for centering images in live preview aren’t working anymore.
With a quick look, it seems this default rule
.markdown-source-view.mod-cm6 .cm-content > * {
margin: 0 !important;
display: block;
}
is affecting internal image embeds now; previously it was only an issue for external image embeds in live preview.
So you could add a snippet of
.markdown-source-view.mod-cm6 .cm-content > * {
margin: 0 auto !important;
}
but that will center all images in live preview. One option is using a cssclass to only center images in a note with that cssclass (both live preview and reading view)
.markdown-source-view.mod-cm6.centre .cm-content > * {
margin: 0 auto !important;
}
.markdown-preview-view.centre img {
display: block;
margin-inline: auto;
}

Had another look and this is working on my end using alt text:
img[alt*="center"],
.cm-content .image-embed[alt*="center"] {
display: block;
margin-inline: auto !important;
}
