I Built an AI Thumbnail Generator Trained on 8 Years of YouTube Best Practices

So, most AI thumbnail generators, they just spit out very generic images that look exactly the same as everything else out there. And so, I actually built one that's trained on 8 years of YouTube best practices. [music] So, it's stuff that I've learned from spending tens of thousands of dollars with the consultants behind some of the biggest channels online. So, let me show you. So, right now I'm creating a video called why I switched from ChatGPT to

Claude, and it's a talking head video on exactly that. And I want myself to be in the image. So, I'm going to drag that and hit generate three thumbnail concepts. And right now it's generating the images with Gemini. And we actually have some decent thumbnails. They're all three completely different concepts. People typically look like me, but I'm using this mostly for prototyping. You can download the thumbnail if you want to know why it works based on

YouTube best practices. I've trained it to do that. This is the image prompt that it came up with that it'll give to Gemini to actually generate these. All right, so let's go to YouTube and let's try something different here. Living with Tom Brady for a day. Yeah, let's try that. So, let's say living with Tom Brady for a day. Let's just say that we want to do something like this. We'll hit generate. It's going to ask

Claude for thumbnail concepts. I'm really curious what this is going to look like. Yeah, and look at that. So, Tom Brady's crazy diet, living with Tom Brady for a day. Tom Brady's in the background. I train like Brady. 24 hours with Brady. I don't really like that one, but the other two are actually kind of decent and they do follow the YouTube best principles, which I'll get into in a bit. So, here's the prompt that I

used to build this thumbnail generator. So, I said, build me a YouTube thumbnail generator as an internal console application for my team. What it does, so it's going to generate three distinct thumbnail concepts, and it's going to render each as a downloadable mock-up styled like a real YouTube feed tile. And for each concept, I want to know in roughly two to three sentences why it's going to earn clicks. So, it has psychological hook, etc. The inputs,

I'm going to give it a working title. I can give it a script or a description, and based on my experience, it works much better with just a short description. And a reference image of a person if I want that person to be in the thumbnail. So, it's going to use the latest Opus model from Anthropic, which is also Claude, uh to generate three concepts following the best practice uh packaging document I'm uploading. So, you can

see that I I uploaded a document up here, and this is basically like a summarized version of years of notes that I've been taking. And for each concept, Opus should write a detailed image prompt. So, basically, Opus is is coming up with these concepts, and then it's going to write a prompt for Gemini, and it's going to pass that image prompt over to Gemini, and it's going to actually produce the thumbnail. So, that's how this is

going to work. Obviously, thumbnails should be 16:9, and the text overlay should be baked in directly to the generated image. In terms of output, we're going to see three thumbnails side by side that kind of look like a YouTube feed, and each one should have a download button where you can download them. Each card should be expandable about why this works. And we're also going to have a history tab uh where we can, you know, generate

different thumbnails and see everything that's been done. And then finally, I just mentioned again that I'm going to be uploading the best practices document for the AI to actually do this. And the tool that I actually ran this in is called Agent A, and it's an AI agent that has unrestricted access to Ahrefs data. So, it can actually pull real SEO, Google, and marketing data, which is super powerful for any marketer. Uh and rather than just

like generating reports, it can actually build stuff. It can do stuff for you. And I'm going to show you why this matters a lot for YouTube in a bit. So, I'm going to walk you through the build now. So, it starts off, says that it understands what I want, and then it kind of asks me questions like Claude has planning mode, and it asks me about style. So, like how do I want it to look here?

I just said that I wanted to have a generic placeholder, so do you want to upload like your brand logo and stuff? I don't really need that, not a huge deal. Um should you be able to delete stuff? I said no, let's let's keep the history permanent so we can actually see the different um versions that we have, especially right now it generates three, so let's say that I wanted to generate three times and I'd have

nine thumbnails to look from. I can see them all side by side on one screen and actually decide what I want. And then there's just one other technical question here about um Gemini. So it has all the answers that it needs, it goes through and it actually starts building everything. Very similar to the way that Claude works and it makes sense because we're using the Opus 4.7 model. Whole bunch of different models that you can use

here, there's actually a free one here, too. I haven't tried and it's basically just walking you through the thought process and everything that it's actually doing to build what it needs to do. Roughly 16 minutes to complete the build of this thumbnail generator tool. And this app only cost me $3.29 to build. And so this is what we ended up with. You just enter a title, a description, you can upload an image if you want and

then it'll actually build a thumbnail for you. So let's try to go into YouTube here. Um can we survive a one-star golf course? Okay? Build the thumbnail here. Can we survive a one-star golf course? I love YouTube golf, by the way. I'm going to drag and drop an image of me here. Just use that same green screen one and it's actually really good at changing the expressions. It's pretty standard photo of me, right? Making like a

a no expression face, like right? Nothing crazy there, so I'm going to hit the generate thumbnail. Our original sample is right here. Yeah, you know, like these thumbnails are actually like quite decent, like I really like this thumbnail. Uh I would totally use this. Anyway, let me walk you through some of the YouTube best practices so you can see that it's using um contrasting colors, so the blue and the green here. It has the hint of

yellow here. One thing that a lot of people who create thumbnails do is they put too much inside the thumbnail. So, in the actual training document, it should limit it to only three focal points. So, if you look at these thumbnails, at least the first two, that's exactly what you get. So, you get me in all white, which contrasts from this color. You have the club here, and then you have the dirty course, like with long

grass. Here, I actually really like this thumbnail. We have a bigger close-up photo of me pointing towards what? A golf cart that's sinking here. So, we have focal point one, focal point two, large or really good contrasting colors here, short text. Some people put in way too much text. People aren't reading that. And so, this is basically how it works. It And if we go through the history, you're going to see some of those best practices

come into play here. Same thing here. We have one, two, three. For these ones here, uh do YouTube ads actually work? We made a video on this as well. And I actually really like this thumbnail here. It's really bright. So, using bright colors is good. Yeah, so that's basically it. But, I want to show you why I built this in Agent A rather than Claude or another tool. And so, if you remember before I said that

I built in an Agent A because it has unrestricted access to Ahrefs data, and that's actually going to be super helpful for YouTube. So, what I did here was I asked it to find me three high-traffic keywords in the digital marketing niche, cuz that's where we are, where the YouTube videos are currently ranking on Google's first page. So, if you've been paying attention, there's YouTube videos pretty much in every single Google search results page. Um and

if you can rank your videos there, then people are going to click them and you're going to get more views doing that. So, it's basically video SEO plus YouTube SEO, and I'm asking Agent A to find me which keywords I should be ranking for in Google and in YouTube and then to provide me with with those keywords are. Give me working titles that I can use to rank for it. Give me the YouTube URLs that are

ranking so I can actually see data on these videos. And then I want you to actually run it through the thumbnail generator that we just created. And so this is what happened. Took my my query and it figured out exactly what to do in Ahrefs. So it went into keywords explorer and it found digital marketing keywords and then it pulled the SERP which are the search engine results pages. It's just a two to three working titles

and and then it ran it through the thumbnail generator. So it's basically creating that plan so I can see what it's doing. It goes in, it pulls all that data, bing bang boom, eventually it comes down to 5,197 rows here, 200 different keywords and it's just giving me three of them. So it says the keyword is Facebook Ads Library, search volume of this, keyword difficulty of this, potential traffic of this, which I would say is an

overestimation. It tells you the intent of it which is informational which means that we can create a YouTube video on this and it says that the existing number eight video gets roughly 328 visits per month to that video. So let's see here. We can actually click that video and you can see right here the views to this video. It was published a year ago and this is the graph of a video that gets search traffic. It's

passive, it's consistent, and it continues to grow even though the video was published a year ago. That's not how YouTube works for anyone who's, you know, getting views through browser suggested. This is very much a search based videos. That's affirmation for me. So check this out. Um it gives me working titles to consider. So I spied on the top brands and you know, you can just say like how you can just change this in and create

the same video. How to use Facebook Ads Library to find winning ads. Like you can create the same video. You can create both if you want. Um but yeah, it gives me this this title here, Facebook Ads Library, which is more likely to rank. It's like a hybrid between search and browse. If we wanted to, we could have adjusted the prompt to say that we want search-focused titles if that's strictly what we're going for. The next

one that it came up with is email marketing services. Right? We have some titles here like I tested 26 email marketing tools. We can call it email marketing services if you want to go verbatim. Uh and it comes up with these different thumbnail ideas, right? How to start affiliate marketing. It shows you all the search data here. And then it shows you different titles. And then it says, "To view or download the actual generated thumbnails, open

the history tab in the thumbnail generator panel." And we can see the three that were generated here. So, this is actually a decent thumbnail for what it is. So, let's say I wanted to download this one. I can send this to my thumbnail designer, and he can go out, use his essence inspiration. I can say this is generally what I want, but I want to change the text to this or that. And you can actually make

adjustments directly in the chat. So, let's say that I don't like the way that the tool is, or there's a feature that I want to add to it. Then I can just type in the chat exactly what I want, and Agent A will go and make those adjustments. Now, if you want this exact thumbnail generator, you can build it yourself using the steps and prompts that I just walk you through. Or if you've got an Agent

A workspace, you can actually just download it by clicking on apps, click on install beside thumbnail generator, and it'll be in your workspace. And if there's anything that you want me to build for you, just tell me in the comments below.