@Mimishu1995: I am no expert, but what I learned from some folks who have been published (colleagues, grad school people, friend) is that major comic publishers (Marvel, DC, Image) want see that you already have published by smaller publishers. It’s frustrating because it’s like the old axiom that you can’t get a job without experience and you can’t get experience without a job.
That said, there are a number of smaller publishers (Action Lab, Black Mask, Dark Horse, Lion Forge, and Comixology Originals) that do accept story proposals. The rub is that they want your comic to basically be completed for them to consider publishing it.
In my case, I have the first 2 (of 3 issues) all done, so they were comfortable that I’d get issue three done. Plus the script, layouts, and cover design for No. 3 are all done. They also wanted all the digital files ready to publish. Luckily, I’m a graphic designer, so I know how to do that. Essentially, this means they have to very little work if they decide to publish your work.
Of course, they still have to want to publish it. The folks I spoke with say there is a large market for Young Adult (YA) material. Luckily, my book is an all ages, family adventure story. Even so, I submitted it to Comixology Originals three times. The first two attempts I didn’t even hear back. Not a rejection, just (I assume) a “we’re too busy to even look at this.” Third time, they got back to me in a month with a “congratulations, we would like to publish your book” email.
It’s a small victory, but the idea is to be able to say you have been published to get the attention of larger publishers, who are constantly trolling smaller publishers for new talent. At least, that’s the theory.