The chances are that you or someone you know has accidentally deleted a picture. Memory cards get reformatted, images get culled, and sometimes we lose the only copy of an image we wanted to keep. I’m not going to go over the importance of backing up your files as it has already been covered extensively here. What I am going to tell you is is how to recover images from a memory card. The three main ways that lead to image loss are: card corruption, deleting, and reformatting.

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What Causes Card Corruption?

Memory cards are tough. It seems like every other week, there is a story of a camera being found in a body of water with the images still intact. That is because the memory cards themselves are arguably sealed better than most entry level DSLRs. Many are effectively waterproof, even if they aren’t marketed that way. In most situations, the plastic casing is a risk more than the electronic internals.

[Rewind: 6 Key Mistakes To Avoid When Handling SD Cards to Minimize Data Loss]

Physical damage to the card can be easy to spot, but you can have corruption and data loss without anything fundamentally going wrong. The most often occurrence of card corruption is when you remove your memory card before the images are done writing.

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The firmware in cameras and card readers can cause errors and wreak havoc when writing images, especially when it is put in situations it can not handle. Trying to record HD video on a class 6 card? The constant stress on the card from the heavy workflow can cause write errors.

Shooting with an almost depleted battery will cause an invalid write of the image. Sometimes, you will get lucky, and the image will either transfer completely from the buffer or it won’t write at all. A partially written image can also spell disaster for your images and sanity. It only takes on bad apple to spoil the whole bunch.

Continually shooting and deleting images when the card is full can also cause corruption. Filling your memory card to capacity may cause your camera to overwrite the card header, making the card unreadable. A safe practice I follow is to leave at least 2% of the card empty. For all of you that hate math, that is somewhere between 20-30 images depending on resolution and card size.

Accidentally Delete an Image?

Sometimes when culling images, you can accidentally delete an image that you wanted to keep. It happens from time to time. It’s an inconvenience when working on your computer and scary when you’re culling in camera. But when you delete an image, the file isn’t gone forever.

The information is not erased when you delete a picture (or any other file). Erasing images tells your camera that it’s okay to write over the images already on your card. So you will not actually remove images, but just take images over the existing ones. This will always leave ‘traces’ of data on the card.

Why Formatting Is Important

Formatting helps clear the card of extraneous files that build out from prior use. So you will start off with a fresh, data free card. Formatting doesn’t erase information either; it instead creates fresh blocks, and a writes a file system. Recovering images from a formatted drive is possible if you do not use it after the format.

[Related: How To Really Format SD Cards For Optimal Performance]

It’s kind of like carbon paper. There are two pieces of paper. Writing on the top sheet will make an impression on the bottom sheet. Formatting would be comparable to putting white out on the top piece; the information would still be on the sheet below. However, if you were to then write on it, it would be imprinted over the top of the original on the bottom sheet. You would be unable to read any of it.

How Do I Recover Images from a Memory Card?

If your card becomes corrupted, you delete an image, or accidentally reformatted it, stop using the card immediately. If you continue to use the card, your images may be lost forever. Programs like PhotoRec, which we reviewed a while back, can help recover images if your card is still readable.

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[Related: Save Your Images, Clients, Sanity And Your Liver, By Recovering Lost Files For Free]

There are a variety of programs that can help restore your images; some are specific to image formats like .jpg, and others offer a wider range. For those that find PhotoRec’s text-based interface daunting, there are alternatives like Recuva (Windows) or Exif Untrasher (Mac).

Good image recovery programs have a great deal of success. However, recovery is not 100% guaranteed (especially if you continue to use the card). Sometimes only a few files are recovered, or none at all. If your images are not recoverable by consumer method or your card is completely unreadable, you stand at a crossroads.

If you can part with your images, the cheapest alternative is to toss the card and get a new one. If the images on the card are of a recent event, a child’s birthday or they are for a client, consider checking the warranty of your card as some manufacturers may attempt recovering the images for you at no cost. If all hope is lost, companies like LC Technology will attempt data recovery, but at a high cost.

It is a safe practice to recycle your cards to prevent corruption in the future. When purchasing a new card (or drive), write the date you bought it somewhere on it. After about three to four years, get a new one and retire the old card. If you are in the habit of taking thousand of pictures a year, you may want to retire the card every year due to heavy use. Memory cards are cheap enough that they can be replaced twice between camera upgrades and can prevent an expensive amount of problems.