Orders from the Command Bunker #4 : Emulation Station Box Art
As promised, here's a more in-depth article regarding the collection, formatting, and display of box art within Emulation Station. If you need guidance regarding Emulation Station's metadata, please reference, 'Orders from the Command Bunker #3'.
I highly recommend you use the Universal XML Scraper vs. the Pi's built-in scraper, or Stephen Selph's external program. As I previously wrote in the last article, because the Universal XML Scraper is PC-based, it provides you with an excellent interface to extract, edit, and SFTP the content to/from the Pi compared to working directly on the Pi. Like most people, I don't speak Linux, so having a Windows-based solution is right up most people's alley. If you need help running the Universal XML Scraper, again, please reference the previous Command Bunker article. For the sake of brevity, we'll assume you have already scrapped your box art, so now what do you do?
Note that by default, Emulation Station uses an '-image' suffix for all box art (i.e. Super Mario Bros.-image.png or Super Mario Bros.-image.jpg). You don't have to keep this structure if you don't want to, though if you need additional re-scrapes, it is the default format from the automated tools, so I ended up simply keeping it.
Now, let's take a deeper look at the content you scraped.
Note how some games/roms don't have any associated images because the scraper could not locate any matches. In these types of scenarios, you can try re-naming your rom, then re-scraping (i.e. change 'Double Dragon 2' to 'Double Dragon II'). The automated matching is not perfect though, so you'll likely end up making manual entries and adjustments at some point, especially for Japanese roms.
Regarding the manual collection of box art images, while you can always use Google image searches, I want to recommend another site that was invaluable to me. Specifically, I am referring to 'EmuMovies', which is a great site to download entire collections of artwork by console via a single action. Unfortunately, this site requires a registered profile to download images, which is a bummer, but you can always make a fake account using 10-minute mail, or another similar site. The free content from this site is pretty extensive and high-quality, making it well worth the effort of creating a dummy account. Simply download your desired content, extract it from the archive, and then sort through what you need.
The 2nd issue you're going to notice is the content is not uniform in regards to image quality or dimensions. Depending on your level of OCD, you may wish to have all of your system-specific box art contain identical dimensions, aspect ratios, file extensions, etc. While you certainly do this manually, you have several additional automated solutions at your disposal, though not all of them are free. I ended up using another free program titled, 'IrfanView', which is an incredibly functional tool for mass-modifying images. Though we are not endorsed by this developer, I cannot speak highly enough of this product as it has saved me hundreds of hours of time via its batching functionality. With this tool, you can mass change your images to a different format (i.e. .jpg to .png), to common dimensions (i.e. force all SNES images to display as 480x680 pixels), add/remove titles (i.e. scrub the phrase '-image' from your file set), or do all at once. As is my understanding, Photoshop can do most if not all of these same batching functions as well, though that product is not free, nor do I personally use it. 'IrfanView' is a handy program, beyond just the Pi, so try it out.
Regarding image quality and clarity, every once in awhile, you are going to come across an image that is pretty good, but it could be improved. For example, the image is a little too dark, or there are smudges or creases in the source material. For these scenarios, assuming the image can be salvaged, I recommend you run your image directory into the MS Office Picture Manager (or Photoshop if you have it). From this interface, you can adjust the image's brightness, saturation, contrast, etc. It even has an 'auto-correction' feature, which is nice, though I argue it tends to create overly bright images. At least in my experience, after hitting the 'auto-correct' button, I would typically manually reduce the image's brightness by 5 increments.
To correct minor coloring issues, MS Paint is another handy program to use. Simply match an existing color from the image, color over your imperfection, and save. Since the preview is fairly squished within Emulation Station, you actually have quite a bit of leeway when it comes to inconspicuously covering up imperfections with Paint, so have at it.
At this time, you have 2 major decisions to make:
1) What format do I want my images to display as - namely .jpg or .png?
Though the Pi can display either format, the issue really boils down to image quality vs. size, where .png looks better than .jpg, but consequently results in much larger file sizes (maybe 3-5 times larger). You can mitigate that tradeoff a bit using smaller dimensions for your images, but at some point, you begin to counter the point of using a higher-quality .png images. What did I end up choosing? PNG, as to me, the image quality was worth the increased size allocation. Using the above mentioned program, 'IrfanView', you can easily mass change your core/system-specific images to either format, so experiment and see what you like better.
2) What size/dimensions do I want my images to display as?
That's a tough question as there doesn't seem to be an agreed upon standard when it comes to box art displays. For example, should I force all of my NES box art to display as 480x680, 496x680, or something else? What should I do for Japanese-games, which are horizontal-based vs. vertical? When it came to my Pi, my goal was to get as close to the original aspect ratios of the physical media as feasibly possible. Are these 100% accurate? Probably not, but then again, they seem close enough to me. In the end, it's really your call and personal preference that matters. Same as above though, 'IrfanView' can easily batch all of your images to a common resolution, though keep in mind, there are limits when it comes to stretching out smaller images into larger dimensions.
Here's a chart of what I ended up using.
Finally, here's some general troubleshooting advice regarding your box art NOT displaying within the UI:
1) Ensure your file name matches what is listed in the metadata, such as file name-image.png or .jpg (i.e. Super Mario Bros.-image.png vs. Super Mario Bros..png are not the same thing).
2) Ensure your file name is an exact match to the specifications as listed in the metadata, including capitalization (i.e. Super Mario Bros.-image.png is not the same thing as super mario bros.-image.png).
3) Ensure your file extension matches what is listed in the metadata, including identical capitalization (i.e. .PNG is not the same thing as .png in Linux).
4) Confirm you actually have an image for that game/rom, as it's easy to miss something when you have to manage hundreds, if not thousands of entries.
I hope this supplementary guidance was equally as helpful as its sister article. While tedious and time-consuming, box art really makes your Pi's UI pop. Sometimes, I just look at my collection rather than actually play anything. In any event, enjoy.
Emulate This is not sponsored by, nor were we compensated by any of the following companies/products: IrfanView, EmuMovies, Photoshop, Microsoft, Google, 10 Minute Mail, or the Universal XML Scraper. We are gaming fans and only wish to share our hobby with others.