Should I reduce the size of my photos?

My DSLR has a resolution of 24 MP (6000x4000px).
My photos saved as JPGs are approximately 10 MB in size.
Since I’ve got fibre, uploading this kind of file is not a problem, but I feel guilty imagining the server resources needed to store our millions of photos.

There are of course desktop tools to reduce the size of images, but I don’t know what the recommendations are?

When I think about it and it doesn’t harm identification, I change them to 1920x1080. But sometimes I’ve forgotten, so I was wondering if it wouldn’t be a good solution if iNaturalist offered a native image resizing tool?

I thought there was an upload plafond from 20 MB,but there is not anymore ? In the past identification did not need many pixels but i have no idea about the present technology

We’re going to keep the limit at 20mb for a few reasons:

  • image processing is one of the bigger slowdowns on iNat, and processing larger images would make this even slower.
  • bigger images mean longer observation upload time, and they might also cause issues on the client side depending on one’s set up.

It’s possible that at some point we can do the image processing on the client side, but there are a lot of variables there, and we’ve had issues with doing it in Android

I think iNat reduces all large photos to a maximum of 2048 pixels at the widest, so I suspect you don’t need to do anything. I do crop things like insect photos to show minimum background and maximum insect.


In fact, I just checked by uploading a 6000x4000 photo, and it was resized to 2048x1365 in the “original” version :
Okay, so I’ll just crop when necessary, but I won’t bother resizing the photos anymore!


I reduce all of mine to a maximum of 10 inches on the longest edge and 300dpi, with Quality (a Photoshop .jpg save setting) set to 10.

This keeps good detail, but keeps the file sizes down to between 1-3 MB.

This is well within the iNat limits and the images don’t get unnecessarily compressed on the site as a result.

Contrary to the answers above, you should crop your images to as close to the maximum of 2048 x 2048 or square. Especially for SLR’s and similar cameras that use a wider sensor. In the above example the image is somewhat unnecessary reduced to 2048x1365. It may not sound much but the effect on photo quality can be so dramatic that it often is not possible to ID something satisfactory. At that resolution the number of stamens in smaller flowers is impossible to see. A crop of the original would have enabled me to do that. Cropping has the advantage of isolating the subject more clearly, which is often not the case in a wide panorama.

Cropping is quite easy with most software and it means that that the photo uploaded is very close to what is displayed. It also have the benefit it shows the subject in a grid, which is often not the case when the subject is not centre in a panorama.

There are many photos that were already cropped as a portrait or landscape. Or occasionally screenshots of phones with unnecessary large black blocks at either end. Very often these are impossible to ID because of low quality.


Unless you REALLY don’t like processing your photos on the computer, I’d recommend always wisely cropping and/or resizing, plus optimizing if you are able. Leaving it to automatic resizing/compression functions such as the one used by the iNaturalist platform inevitably leads to some degree of loss of quality and this may be decisive in cases where detail is important for an ID. Also give a thought to those of us without a rapid internet connection, the smaller the file size (for the same quality), the happier and more nimble we are.

1 Like

In my photo editing software, if my cropped photos are larger than 2048 px on the long edge, I’ll export them so that they’re not longer than 2048 px on the long edge. And export as a jpeg at 100% quality. If they’re smaller than that, i don’t resize them at all.

1 Like

I know theoretically the resize/compression algorithm on editing softwares should give better-looking results than the one iNat uses (since I expect it prioritises resource use and speed), but in practice I’ve never noticed much of a difference. Is your experience different, or is it a “might as well while I’m editing”?

This and also why make iNat upload those large files? The uploader uses a lot of RAM, might as well not overwhelm it.

FWIW I’ve tried both methods and I don’t see any real difference, visually.

1 Like

This is obviously what I do for species with complicated determinations.
But in the example I sent, this is not at all compromised by the resizing on the uncropped original.

I take the time to crop quite often, but it’s true that to upload a lot of photos, it takes time…
It’s a happy medium to find, but if I can save time sometimes by not cropping/resizing, it allows me to post more observations.

(for example, I practice “night hunts” for moth, and I sometimes have hundreds of species in one evening… For resizing, I can do it in batch, but for cropping, it’s manual and therefore very tedious)

1 Like

The irony is that many people do crop their images, but to make it 2 times as long as wide. In this case the image degradation could be significant and perhaps is causing the subject to disappear in a square grid display. This is even more of an issue in future as many cameras and cellphones are coming out with 50 mp cameras.

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.