: How can I increase the size of a .jpeg without losing quality? Is it possible to make a .jpeg photo larger without losing "quality"? I have a photo that is 450px x 750px and would like to

@XinRu324

Use SmillaEnlarger, which you can find here for free:
sourceforge.net/projects/imageenlarger/
Of course you should not do this. You should not even want to do this. But I hate it myself when people try to tell me what to want.

=== an aside === The best way is to paste this bitmap into Inkscape and take some time (yes) and trace it and make a new vector graphic. That way you can even add some minor changes and have your own colours and possibly avoid copyright issues (I am not an expert on how much you would need to change to make it your own.).

Then export from Inkscape as a PNG and you have a phantastic new, crisp bitmap in any resolution you need. === back to my main answer ===

We have used SmillaEnlarger when we absolutely had to. Not ideal, but the best tool we have found and used so far, for boosting old bitmaps for quick jobs. It takes time to learn about Smilla and its settings-options. So if this is just about this one illustration, your time might be better spent by tracing the dragon. hth

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@Michele215

Ok and oldie but goodie question; here I go:

Some definitions/aclarations:

1) Quality is a process, is taking care on each step of it.

In a case of resampling an image there is no "quality" loss, (except if you make mermelade of your own photo, probably compressing it like hell) What you have is information loss when you downsample it. You have a "information guess" when you upsample it.

2) There is no CSI program that perform miracles in the terms you need (However, I have seeing some forensic image processing program that fairly shows a licence plate from a very low resolution image, or from a very narrow angle. The result was ugly, but you could clearly see the licence plate.)

3) So, the programs use diferent "guess" methods to try to asign information to the new pixels.

Some real tests

Here is a controlled exercise of resampling. Reset your browsers zoom so you see them in real size.

a) In the center are 3 images. The reference image is the one marked 100%

b) Next to it there are some smaller marked as 300% and 200%. They are 1/3 and 1/2 respectively, when they are upscaled they will have a resampled ratio as marked.

The programs used (in order of appearance):

1) Just scaled (this is the so popular "pixelation", the technical name is "nearest neighbour") 2) Irfan view Lanczos Filter

3) PhotoZoom 4) Reshade





Photo: Scott F. Snyder
Model: Amy Lee Fathbruckner


The normal Photoshop bicubic filter looks simmilar to Lanczos Filter.
This is an oldie test, there is a chance the programs now make a better result, but do not expect a quantum leap.
They have no aditional process. You can add a small sharpening after the initial resampling. Photoshop has one marked as bicubic sharper.
I would resample in round numbers. Not 150%, not 234.567%
If you simply strech it inside Ilustrator or simmilar, the result will be like sample No. 1.


Conclussion

In my opinion, a 200% upsampling is acceptable. A 300% just in case of backgrounds.

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@Michele215

PhotoZoom Pro 6 creates larger images (up to 1 million by 1 million pixels), it also produces higher quality results. PhotoZoom Pro 6 is equipped with S-Spline Max, a unique, patented image resize technology which excels at preserving clean edges, sharpness, and fine details.



Gimp is a free software. It can also be used to resize images with minimum quality loss. However, I should warn you that the result will not be as good as PhotoZoom.

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@Sent7350415

As stated you cannot increase the size of a .jpeg without loosing quality but there is a margin of tolerance that you can increase the size of a .jpeg before it is noticeable.

Take my hero for instance (original file):



If I import this image into Photoshop and go to Image > Image Size (Shortcut Ctrl+Alt+I for PC or option/alt+cmd+I for Mac)



Change pixels to percent



You can change the percentage to 110% and repeat this till you receive a notable difference in quality. NOTE IF the image is high quality you can usually do an increase no more than 10 times from experience but as stated, this depends on the quality of the image you are adjusting.



Finished:

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@Merenda852

To say it short: No.

Images in jpg format are not vector based images. Vector based images can be resized without to lose quality. Bitmap images contains colored pixed. If you try to double the size one pixel has to grow to 4 pixel with the same color. Result: If you want the image 3 times bigger you will see the original pixels in your image.

It depends on your image if it is changeable to vector format or not. An usual photo (portrait of a human, mountains, landscape etc.) is not changeable to vector format.

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