Why CBZ Files Are Format Traps (And Why This App Exists)

Honestly, nobody actually keeps 2000 comics on their Mac internal drive. I certainly didn't; my 300GB collection lived on an external drive because a 512GB MacBook Pro simply can't breathe with that much dead weight. But offloading the files to a NAS or a USB drive creates a different kind of friction. You end up with a library that is "safe" but completely inaccessible the moment you want to curl up on the couch with an iPad.

The storage and access problem

A single manga issue can hit 150MB, meaning a full series quickly devours multiple gigabytes. While storing them on an external drive solves the Mac's storage crisis, it breaks the reading workflow. Most iPad comic apps are not built to browse network shares or mount external volumes reliably; they expect the files to be physically living in their own local sandbox.

Even worse, these apps don't just "read" the files; they cache them. When you finally suffer through moving a few CBZs over, the app decompresses every image, often doubling the storage footprint on your mobile device. You end up managing a mountain of external storage plus an ever-growing pile of iPad cache that you have to clear manually just to make room for the next volume.

The iPad transfer nightmare

I expected the iPad to be the savior of my reading habit, especially for color manga, but getting a CBZ onto it is a genuine chore. Since you can't just point an app at a cloud drive or a NAS and expect it to "just work" like a streaming service, you're stuck with prehistoric methods.

So here’s the reality of the options:

• AirDrop: It technically works, but moving a batch of 150MB files is slow and requires both devices to stay awake and unlocked for the duration.
• Manual Copying: You have to plug the iPad into the Mac, open Finder, and drag files into specific app folders—one by one—assuming the app even supports that import method.
• The Cloud "Solution": You can pay for a 2TB iCloud or Google Drive subscription, but most comic readers don't natively "stream" CBZs from the cloud. You still have to download the massive file to the device before you can turn a single page.

The friction is so high that I eventually stopped reading altogether. I was spending more time managing file transfers than actually finishing chapters.

The cloud incompatibility problem

The real frustration is that the rest of my reading life is seamless. My books in Google Play Books or Kindle sync perfectly across my iPad, phone, and Mac. I can start a book on one device and resume on another without thinking. CBZ files completely break this.

Google Play Books and the Kindle Paperwhite—which has a beautiful, glare-free e-ink screen—simply do not support CBZ. To use them, you have to convert the file, manage multiple versions across different drives, and manually track your reading position. Once you finish a comic, you can't just pick the next one from a synced library; you have to go back to your "storage" and start the transfer dance all over again.

Why EPUB solves these actual problems

EPUB is the industry standard for a reason, and moving my collection into this format changed everything.

• Cloud Integration: It works natively with Apple Books, Google Play, and Kindle, allowing your reading progress to sync automatically across every device you own.
• Storage Efficiency: EPUB files are often 30% to 50% smaller than CBZ because the format uses compression more intelligently.
• Device Flexibility: You can jump from an e-ink Kindle to an iPad to your phone using the same file, picking up exactly where you left off.

The solution I built

Tired of the friction, I built (ComicToEPUB). It does not just "hack" a conversion; it reads the pages properly to maintain image quality and creates valid EPUBs that modern reading platforms actually understand.

The best part is the "watch folders". I can point the app at my external drive or NAS, and any new CBZ or CBR files automatically convert and sync to my cloud library. I even set up specific folders for manga to handle right-to-left reading. Now, when I download something, it just appears on my iPad and Kindle without a single manual transfer.

The actual problem

CBZ served its purpose when we only read on one computer and disk space was the only concern. But today, we need our libraries to be flexible. CBZ is a bottleneck that keeps your collection trapped on a hard drive. EPUB has been the standard for twenty years; it is time our comics finally started acting like books.

Next: Building ComicToEPUB: Why Watch Folders Changed Everything