How To Convert and Resize Images On Your iPhone

Hi, this is Gary with MacMost.com. Let me show you how to resize, compress, and do other things with images on your iPhone. 

Previous to iOS 26 it was surprisingly difficult to export a photo from the Photos App or take an image in the Files App and resize it and compress it in a different format. You can do it using a shortcut that you created or you could use a third party app. But in iOS 26 we now have the Preview App on our iPhones as part of iOS. You can use that app to do all of this and more. Let me show you how. 

So as my first example I'm going to go into the Photos App. Let's say we want to take a photo, like this, and we need to send it to somebody or upload to a website. The only problem is this image it too high resolution. The website will reject it because it is too big and we don't want to send that big of an image to somebody over email. So we want to make this image smaller. The way to do this in iOS 26 is to send this image from the Photos App to the Preview App. 

The first step is to send this image from the Photos App to the Preview App. In the Preview App we can manipulate it in all sorts of ways and export it in a new format. To do that I'm going to tap the Share button at the bottom. The typical way to get content from one app to another. Now with this selected I want to look in the row of icons here for Preview. If you don't see Preview here scroll over until you do. If you still don't tap More and then here you can Edit and then use the Plus button to the left of the suggestions to add Preview to the top of the list. I moved it all the way up here under AirDrop. So that's why I see it right here as the second item. So all I need to do now is tap this and Preview opens and this image goes into it and creates a new document. You can see that it is a new document by looking at the name up here. This is what the document is called. It's using the same name as the File Name from Photos. 

But we haven't done anything to the image yet. It is the same image. It's just now a file instead of in the Photos App. Now for this first example let's just do two simple things. Let's resize it and then export it in a different format. Then in the next example I'll show you how to do even more. So, to resize it go to the three dots button here at the top. Tap that. This takes you to the Adjust Size Screen where there's a lot you can do. But chances are you probably just want to change the width and height. You can set the units here. I'm going to leave it at pixels but you can change it to percent or inches which would then use the Resolution Setting here. But most likely you're doing this because maybe some website told you it's got to be 1000 pixels or less on one side. So I can just change this number here to say 1000 and you can see the height adjusts automatically because of this switch for scale proportionally. If you turn that off then the horizontal and vertical dimensions would scale differently and it would stretch the image. 

Now we tap the checkbox here and now it is only 1000 pixels wide. We've successfully resized the image. So now that we have it at the right size let's export it. To do that tap on the File Name here. You get some options having to do with the file. It's kind of like the File Menu on macOS. Here we can move it, rename it, and all that and most importantly for our purposes export it. The export image screen lets you pick the format. So it is still at HEIC, which is a great format to use on your iPhone to get smaller pictures and fit more of them on your iPhone. But for more compatibility, say uploading to websites, sending it to somebody, and you don't know what they've got you might just want to use the good old jpeg format here. Now notice the size. We can adjust this and this is going to compress the image more. This will only be available if the format you've chosen allows compression. HEIC does and JPEG does. So we might want to get to say under 100K, like that, because maybe that's the restriction for the website we're uploading to or something. So we pick a size that's there. Then we use the Check there at the top. Now it's going to ask us where to save it. This is a regular Save dialogue here. It's referring to the Files App. So let's go up here to the Documents Folder and let's say, let's go into the Images Folder here and there is a bunch of images in there already. Let's change the name. We will do that here at the bottom. It says Save As. We can tap that and now we can name it something else. So we'll just name it this and then we'll tap Save. Now we've exported the image as a JPEG with pretty high compression so it is under 100K and we had resized it to 1000 pixels across. 

If we now go into the Files App here and then look in Images we can scroll down and there at the bottom is that Zebra File. You can see its size there and it is ready for us to do whatever we want with it. Attach it to an email. We can use it for whatever purpose we needed that resized image. 

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Now this is probably a longer process than it needs to be. You can still go and build a shortcut if you want to just automatically resize images to 1000 pixels wide compressed JPEG. But this allows you to adjust all of that along the way. You can do it even more. So let's try another image here in Photos. I'll take this one and we'll do the same thing to start. I'm going to tap the Share Button here and go to Preview. This creates a new Preview Image File. We can see it there. Now we can resize it if we want. But let's go first and crop it. To Crop first we select it here and then we can adjust the cropping. So I can make it something like this. Once I've got that I can just tap it and I have Copy and Crop. I'll do Crop so now I've cropped it to this size. Let me enlarge it a bit so I can see what I've got. Now we can also tap here for the Markup Tools and we can draw on it if we want, like that. I don't really want to do that so I'll Undo. But you can do other things. Like, for instance, add text, add stickers, add shapes like arrows and such to it. Whatever you need to do. 

So there's a lot you can do right here to mark it up before you go to the next step which might be that you want to adjust the size or maybe you don't. Maybe you just want to leave it a full resolution. It's already cropped in quite a bit so it should be smaller anyway. So let's go now, right to the Export option here. Now I can choose the Format that I want. I can get the compression down under a certain size, like that. Then the Checkbox there and I can name it what I want, like that. Save. Now we go into the Files App and here we go. There's that image as well as the previous one. 

Now there's one small issue with this process that I want to point out. It is that it leaves behind that original image. Remember when we first jumped from Photos to Preview it created an image file, basically exported from Photos as a file. Where is that file? Well, in the Files App if you go up to the top level iCloud Drive, there's a folder for Preview. In there, that's where it is dumping these. So it puts the file there and when we resize them and crop them it actually changed the image here. That's why these file sizes are smaller than what you would expect. On of them's been size adjusted and the other one has been cropped. So we have these here and we can leave them here but it may clutter things up and then you've got these duplicates that you probably don't need anymore. So it might be a good idea, from time to time, to go into the Preview Folder and then swipe and delete these files if you no longer want them. 

The ones we exported, of course, we exported into, in this case, Documents and then Images. They're still there. It's just those temporary ones, the ones that Preview was working with before we exported that are kind of hanging around. 

Now you can also you this same technique with an image that is already a file. So if you've got a file somewhere in the File's App, if you've saved something from the web or used another app and exported it as a file you can go to that individual file. So I'll go to this one here. It actually is going to open up in Preview. When you tap Files in the Files App now you could see instead of just showing you a kind of quick look of it, it opens it in Preview. So, just like opening the file we're in Preview now. We can access the Adjust Size. We can access the Export right here. But keep in mind if you adjust the size or maybe use this cropping tool you'll be changing that actual image file. So one of the things you may want to do first is tap here and Duplicate the file and then Save it somewhere else. So I'll just save it to this folder here. You can see it gives it a new name and now I can alter this file, maybe make this one the smaller one. I'll make it tiny. Maybe it is supposed to be some sort of icon or something like that. So you can see 100 pixels wide you loose all the resolution. But now if I look in the Files App you see I've got this second one here. This is the original untouched. This is the duplicate that I made. 

By the way if you want to do this with a Screenshot you can. So I'm going to take a Screenshot here by using the volume up and side button at the same time. Then I'm going to tap on the little floating thumbnail at the bottom left. Now you don't have the ability in this Share Menu here to access Preview. It's not in the list for some reason. But that's okay. Because you still have Copy. When you use Copy here, I'll just Close out the Screenshot interface. I can launch Preview on its own and then go back up here and say New Document and say New From Clipboard. Now you can see it takes the Screenshot here and I can adjust its size, so maybe instead of the full amount across I'll make it only 400 pixels across, like that. So now I've lost quite a bit of resolution here by making it only 400 pixels across. But now I can also export it here and then choose another Format if I want. I can compress it to make it even lower resolution but smaller file size if I needed to. 

The Copy method may work for other things as well. If you can't Share out to Preview you can always try copying the image from whatever app it is you're using and then use that new Image Button in Preview to start a new document with whatever image you just copied. I hope you found this useful. Thanks for watching.