CC by SA.3.0

it is up to you how you place your credits in your game/project, but you MUST give APPROPRIATE credit.

so your example could read something like this:

Artwork used under CC-by-SA 3.0 (insert link here for CC-by-SA license)

Flying Lizard by Madjestico.

Stones by who ever

Trees by someone else

when an artist has uploaded a piece of work there is a box in which they fill out how they would like to be credited, "Copyright,Attribution". this is a specific instructions so its impotant that you follow those instructions as they are the 'APPRORIATE' credit. If this is blank then you need do anything other then credit the artist and link the license.

So your example could look like this:

Artwork used under CC-by-SA 3.0 (insert link here for CC-by-SA license)

Flying Lizard by Madjestico OR Flying Lizard by MADJ.

Stones by who ever

Trees by someone else

He also mentions that he would like a link to your project, so all you need to do here is post a link to it in his comment section, or message him.

if you have any other work by another license then you could do the same thing but obvouisly change the title to:

Artwork used under 'License' (link to license) and then list the work under that license.

you will need to do this for every artwork that has a partucular license, you will need to check those 'copyright,attribution' notes.

Also,

If you have made any changes to artwork, including a colour change, or modified it in any way you MUST write this also in the credits, or at least indicate the changes, so...

Artwork used under CC-by-SA 3.0 (insert link here for CC-by-SA license)

Flying Lizard by Madjestico OR Flying Lizard by MADJ.(Modified)

         *added Hat, changed colors, red-green, increased size to 100px - 58px, changed name to "Flying Dragon".

Stones by who ever

Trees by someone else

if you plan on uploading that so people can used then it must be used under same license as the original artwork and include a link.lets say you upload it here on OGA.you would say.

Title: Flying Dragon

then write in your description that it is a modified version of Madjestico's 'Flying Lizard, and include a link to madjestico's work.

you would have to give it a CC-bySA 3.0 license, and give what your instructions would be, you should give a link to Madjestico's original work too, but he hasn't asked ask for it in his 'copyright/attribution, so thtas not mandatory, but is a nice thing to do.

thats my understanding of it, hope it helps.

i'm sure someone will come along and mention anything i missed, or got wrong.

all the best

:)

You could just include a simple text file with your game that lists the attributions if you don't want it cluttering up the game itself (unless the author requires as part of their attribution instructions that they want it to be in a particular place).

For a game I made, I didn't have to make many attributions, so I put them on a credits screen. Heres what it looks like (far right panel). http://waywardworlds.com/games/sdf/assets/img/screens.png

I recommend starting a collection of the art you're going to use.  

It will generate a downloadable credits file - you'll still need to review it for accuracy, but most of the heavy lifting will have been done.

Wow, 500+, your going to be busy, :), theres no way around that i'm afraid, you must follow the license or as you say, you will be in violation, but as @Acranorum says, you could do a text file, like i said at the top of my response "Its up to you how you place your credits" unless there is a particular set of instructions in the "copyright/attribution" notice from the original author, so be sure to check them.

If your using a lot of work, and making changes, i would advise that you make seperate folders on your PC to store that work in, and make notes, it will make the credit file a lot easier to handle when writing your credits, nothing worse when you cant rememer whos works is whos and what those attributions should be.

There is a tab section in you profile (downloads) that you can click and it will give you a record of all you have downloaded here on OGA, which will link straight to the desired piece of work you want to check the license for, very handy tool indeed. :)

All the best.:)

Just want to second Boom Shaka's recommendation to use OGA's 'Collection' feature for this.

Just create a new collection and add the works to the collection as you download them.

When you're ready, simply view the collection in OGA by going to 'My Collections' and clicking on your collection.  Then scroll to the bottom of the page and click 'Download Credits File'

I'd also like to add that according the license text itself, 'appropriate credit' for CC-BY and CC-BY-SA works includes providing the title of the work, the name of the creator and attribution parties, a copyright notice, a license notice, a disclaimer notice, and a link to the material.  Note that this is beyond what most folks ask for in the 'credit attribution' box here on OGA, but it is technically the minimum needed to satisfy the license.  Anything in the 'credit attribution' box should be taken as just additional (and optional) requirements.  

Additonally, under CC-BY and CC-BY-SA, if you have made any changes to a work, you need to say so.  You don't have to say much about your changes, just indicate that the work has been altered in some way.    

Finally, I'll take the bait and ask what on earth you are working on that it's going to use 500+ different art works in it? 

With all those assets, it sounds like he is making "OpenGameArt: The Video Game".