markdown-it/markdown-it

yea, I ended up doing just that, and implemented two major cases where the image is separated from a paragraph by single newline ([ image, softbreak, ...inline-content ] and [ ...inline-content, softbreak, image ]). Doing this makes it non-CM-compliant, but we weren't CM-compliant to begin with (using softbreaks).

For anyone interested, here's a partial implem:

function createToken ( type = "inline", tag = "", nesting = 0, level = 0, children ) {
    const token = new md.core.State.prototype.Token( type, tag, nesting );
    token.level = level;
    if ( children ) token.children = children;
    return token;
}

let skipNext = false;
state.tokens = state.tokens.reduce((acc, token, idx, tokens) => {
    if ( skipNext ) {
        skipNext = false;
        return acc;
    }

    if (
        token.type === "inline" &&
        tokens[idx - 1].type === "paragraph_open" &&
        tokens[idx + 1].type === "paragraph_close" &&
        token.children.length > 2
    ) {

        // case: [ image, softbreak, ...inline-content ]
        if (
            token.children[0].type === "image" &&
            token.children[1].type === "softbreak"
        ) {
            skipNext = true;

            const imageToken = token.children[0];
            token.children = token.children.slice(2);
            return acc.slice(0, -1).concat([
                createToken("paragraph_open", "p", 1, token.level),
                createToken("inline", "", 0, 1, [ imageToken ]),
                createToken("paragraph_close", "p", -1, token.level),
                acc[acc.length - 1],
                token,
                tokens[idx + 1],
            ]);
        // case: [ ...inline-content, softbreak, image ]
        } else if (
            token.children[token.children.length - 1].type === "image" &&
            token.children[token.children.length - 2].type === "softbreak"
        ) {
            skipNext = true;

            const imageToken = token.children[token.children.length - 1];
            token.children = token.children.slice(0, -2);
            return acc.concat([
                token,
                tokens[idx + 1],
                createToken("paragraph_open", "p", 1, token.level),
                createToken("inline", "", 0, 1, [ imageToken ]),
                createToken("paragraph_close", "p", -1, token.level)
            ]);
        }
    }

    acc.push(token);
    return acc;
}, [] );