What is a ROM Image?

Fans of retro games may already be familiar with ROM files or what they normally call ROMs. But what exactly are ROM files, and why are they called as such? ROM stands for Read-Only Memory, a non-volatile memory that stores data and, unlike RAM (Random Access Memory), retains data even when the power is off. Once data is stored in a ROM, it cannot be modified, although modern ROM chips already have the capability of being rewritten to still with limited write cycles. The files that are typically stored in a ROM don’t need any modification in the system’s lifetime, like the computer’s BIOS, a device’s firmware, or the games in arcade boards or video game consoles.

A ROM image or ROM file is a computer file or a digital copy of the original data obtained from ROM chips or ROM cartridges of video game consoles. Reversely, some ROM images are created first for debugging or testing purposes before they are permanently embedded in ROM chips.

How Are ROM Images Created?

The process of copying ROM images from ROM chips or ROM cartridges is called dumping. Dumping requires dedicated hardware, ROM burner, and software to transfer the file from ROM chips to a computer. No ROM dumping machine fits all. Some ROM dumping devices contain a CD-ROM drive to copy the image directly to a CD-ROM. Arcade machines usually have customized PCBs, and each would normally require an individual setup for ROM dumping. Likewise, dumping machines for different game consoles also differ from one another.

ROM files have a .rom file extension, and most often, emulator software is used to open ROM files. Unknown Apple II File and Nintendo 64 Emulation ROM Image are some of the emulation software used to open ROM files. These, however, are not universal emulator software; other ROM files would require specific software to run. It’s best to contact the software developer if you want to be sure which software to use to open the ROM files you have.

What is ROM Images Used For?

ROM images are created for various purposes. The most important purpose is probably data preservation. They are also created to recreate or modify retro games and test files before they are permanently transferred to ROM chips.

Software Preservation

Nothing lasts forever, and the same is true for electronic and digital devices. The main and most important reason why ROM images are created is to preserve the original data. There is a huge possibility of data getting lost, damaged, or corrupted as the system reaches its end of life. Creating ROM images is a great way to keep copies of original data for archiving purposes. ROM images also allow a copy of the original data to be used again on newer systems. Some ROM images are also altered to improve the existing data and work on modern devices.

Game Emulation

This is perhaps the widely known use of ROM images. Who can get tired of playing Super Mario, Mortal Combat, and the likes? Luckily, these ageless video games are made available through ROM images. Since arcades and older game consoles are a thing of the past, retro games are brought back to life through emulator software. In the context of game emulation, emulators are programs that run vintage games from a completely different device on another system. They mimic the behavior of arcades or older video game consoles so the games can run on another system like your PC. You can relive your childhood memories on your PC or mobile devices by simply installing emulators and adding ROM files of the retro games to it. Similarly, you can create your own retro gaming machines from scratch using SBCs (Single Board Computers) like Raspberry Pi and load emulators and ROM images to the assembled hardware. Retro gaming machines are the most popular projects done with SBCs.

Debugging and QA Testing

ROM images are not only used for preserving the software; they’re also used to test the software before loading it to a ROM chip. This ensures that the software is free of bugs and running perfectly before embedded into ROM chips since they can no longer be modified once the program is loaded to the chip.

Unauthorized Downloading of ROMs

Generally, downloading ROMs from the internet or any other form of digital media is not legal. However, for the love of retro games and because original ROM images come at a cost, many ROMs are downloaded illegally. Sales and revenues of game companies have greatly suffered due to unauthorized downloads. Because of this, copyright holders have been taking stringent actions to prevent unauthorized release and downloads of their software, particularly the ROM images of arcades or video games. Nintendo, for example, had sued two emulator websites in 2018 for illegally distributing their copyrighted ROMs. Other companies included security features in their products to prevent unauthorized copying of their software. For instance, Capcom had included a protection algorithm to prevent illegal distribution of their software in their arcade games.

There’s still a lot of Gray areas in the legality of downloading ROMs. Some may argue that downloading ROMs for personal use and not distributing them off the internet should not be considered illegal. Whatever the case may be, it’s better not to participate in piracy and purchase authorized copies of ROMs instead.


ROM images serve a good purpose of preserving the data in ROM chips, whether for archiving, reusing, or modifying the original data. Still, they also play a significant role in software testing. The widely used ROM images today are those of retro games. However, the popularity of retro games led to the illegal distribution of ROMs over digital media like the internet. To help stop the spread of piracy, it is recommended only to download authorized copies of ROM images.

About the author

Glynis Navarrete

A freelance blogger who loves to write about anything related to technology. Born and raised in the Philippines and worked in Singapore for eight years as Technical Support for a wide range of IT equipment. Took a dive into the world of freelancing and now enjoying doing what I’m passionate about while not losing touch with technology.