To get the word out; posting here is a good start. Post on Reddit too. Also, you could try sending a Press Release type email to relevant blogs - they might blog about your app.
Think about SEO and how your site ranks in a Google Search for instance.
If you're sending it out to other blogs, avoid the term 'press release'. It may come with bad connotations from bloggers, who could be getting plenty of random PR already.
Pick the most important theme related sites and hand craft a very concise and to the point email without it looking too generic sounding.
slightly off-topic: i'm not a big reddit user, so i dont know whats what. can you recommend a good subreddit for showing webapps. is there a show-hn-like subreddit?
right, meta tags are also missing at the moment. but generally speaking...its a javascript app, with dynamic content (filters) and only images... the googlebot is not going to apply filters. or maybe he is, i don't know.
I stand corrected. they use Javascript in a headless browser to generate the site previews. Detailed information on how Javascript is interpreted to index sites is hard to find. I would not count on Javascript to instruct Google Bot what to index.
To get the word out; posting here is a good start. Post on Reddit too. Also, you could try sending a Press Release type email to relevant blogs - they might blog about your app.
Think about SEO and how your site ranks in a Google Search for instance.