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How To Change File Size Of Jpeg On Mac

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Open your image in Preview by double-clicking on it. Then choose file and save as. You will see a pull down menu of different file types. Select JPEG from the listing and click on the save button. There you have it, a limited area JPEG of your document. There are any number of reasons to check the size of a file on your Mac - the most obvious being so you can free up space by rounding up the largest files and deleting or moving them. Open the desired image file using the Preview application. In the menu bar at the top of the screen, select Tools, then Adjust Size. A window should appear. On the right side of the window, click the box that states inches and select your desired measurement. But if you decide it's the right way to go, here's what you'll need to do in order to reduce the file size of a PDF on your Mac, via the Preview app. Check out the products mentioned in this article.

The image size (or pixel dimensions) of an image is a measure of the number of pixels along an image's width and height. For example, your digital camera may take a photo that is 1500 pixels wide and 1000 pixels high. These two measurements indicate the amount of image data in a photo and determine the file size.

Resolution is the amount of image data in a given space. It is measured in pixels per inch (ppi). The more pixels per inch, the greater the resolution. Generally, the higher the resolution of your image, the better the printed image quality. Resolution determines the fineness of detail you can see in an image.

Although a digital image contains a specific amount of image data, it doesn't have a specific physical output size or resolution. As you change the resolution of an image, its physical dimensions change, and as you change the width or height of an image, its resolution changes.

Two images (A and B) with same image data and file size butdifferent image size and resolution; C shows that a higher resolutionmeans better quality

You can see the relationship between image size and resolution in the Image Size dialog box (choose Image > Resize > Image Size). As you change one value, the other two values change accordingly.

Constrain Proportions lets you change image size without alteringany image data

The Constrain Proportions option lets you maintain the aspect ratio (the ratio of image width to image height). If you select this option and change the image size and resolution, the image does not stretch or shrink.

The Resample Image option lets you change the size of an image without changing the resolution. If you need to print at a specific resolution, or at a smaller or larger resolution than the current image allows, resample the image. However, resampling can degrade image quality.

Your monitor's resolution is described in pixel dimensions. For example, if your monitor resolution is set to 1600 x 1200 and your photo's pixel dimensions are the same size, at 100%, the photo will fill the screen. The size an image appears onscreen depends on a combination of factors: the pixel dimensions of the image, the monitor size, and the monitor resolution setting. In Photoshop Elements, you can change the image magnification onscreen, so you can easily work with images of any pixel dimensions.

A 620 x 400‑pixel image displayed on monitors of differentsizes and resolutions

When preparing images for onscreen viewing, you should consider the lowest monitor resolution that your photo is likely to be viewed on.

How To Change File Size Of Jpeg On Mac Computer

How to change file size of jpeg on mac os
  1. Click-hold the file information box at the bottom of the document. The box displays the width and height of the image (in pixels, and in the unit of measurement currently selected for the rulers), the number of color channels, and the image resolution (ppi).

    • Select the Hand tool or Zoom tool, and click Print Size in the Tool Options bar.
    • The magnification of the image is adjusted to display its approximate printed size, as specified in the Document Size section of the Image Size dialog box. Keep in mind that the size and resolution of your monitor affect the onscreen print size.

Change print dimensions and resolution without resampling

You might need to change the print dimensions and resolution if you are sending the image to a print shop that requires files to be at a specific resolution.

If you are printing directly from Photoshop Elements, you don't have to perform this procedure. Instead, you can choose a size in the Print dialog box and Photoshop Elements applies the appropriate image resolution.

Note:

To change only the print dimensions or the resolution, and adjust the total number of pixels in the image proportionately, you must resample the image.

  1. Make sure that Resample Image is deselected. If deselected,you can change the print dimensions and resolution without changingthe total number of pixels in the image, but the image may not keepits current proportions.

    Note:

    Resample Image must be selected in order to use the Constrain Proportions and Scale Style functions.

  2. To maintain the current aspect ratio, select ConstrainProportions. This option automatically updates the width as youchange the height, and vice versa.
  3. Under Document Size, enter new values for the height and width. If desired, choose a new unit of measurement.

  4. For Resolution, enter a new value. If desired, choosea new unit of measurement, and then click OK.

    Note:

    To return to the original values displayed in the Image Size dialog box, use Alt (Option in Mac OS) + click Reset.

Changing the pixel dimensions of an image is called resampling. Resampling affects not only the size of an image onscreen, but also its image quality and its printed output—either its printed dimensions or its image resolution. Resampling can degrade image quality. When you downsample, meaning that you decrease the number of pixels in your image, information is removed from the image. When you upsample, or increase the number of pixels in your image, new pixels are added based on the color values of existing pixels, and the image loses some detail and sharpness.

To avoid the need for upsampling, scan or create the image at the resolution required for your printer or output device. If you want to preview the effects of changing pixel dimensions onscreen or print proofs at different resolutions, resample a duplicate of your file.


A. Image downsampled B. Originalimage C. Image upsampled

How To Change File Size Of Jpeg On Mac Desktop

Note:

If you're preparing images for the web, it's useful to specify image size in terms of the pixel dimensions.

  1. Select Resample Image, and choose an interpolation method:

    Fast, but less precise. This method is recommended for use with illustrations containing edges that are not anti-aliased, to preserve hard edges and produce a smaller file. However, this method can create jagged edges, which become apparent when distorting or scaling an image or performing multiple manipulations on a selection.

    Medium-quality.

    Slow, but more precise, resulting in the smoothest tonal gradations.

    Use when you're enlarging images.

    Use when you're reducing the size of an image. This method maintains the detail in a resampled image. It may, however, oversharpen some areas of an image. In this case, try using Bicubic.

  2. To maintain the current aspect ratio, select ConstrainProportions. This option automatically updates the width as youchange the height, and vice versa.
  3. In Pixel Dimensions, enter values for Width and Height.To enter values as percentages of the current dimensions, choosePercent as the unit of measurement.

    The new file size of the image appears next to Pixel Dimensions, with the old file size in parentheses.

  4. Click OK to change the pixel dimensions and resamplethe image.

    Note:

    For best results in producing a smaller image, downsample and apply the Unsharp Mask (Enhance > Unsharp Mask). To produce a larger image, rescan the image at a higher resolution.

More like this

The JPEG (pronounced 'jay-peg') is the most common image format on the Internet, allowing photographers and graphic designers to send files that retain their quality, while not being too large. Created by the Joint Photographic Experts Group, the JPEG standard was first issued in 1992, laying the groundwork for how we share images today.

Need images for your project? Shutterstock's impressive collection of more than 70 million images can help! See what our library has to offer.

Learning how to reduce the size of a JPEG is important, especially when you're sending one via email or social media. With a higher resolution, the image will have more pixels, adding detail that is most noticeable when the image is viewed at full size. However, this also increases the file size, and this can be problematic when creating web-friendly content.
Generally, a resolution of about 70 pixels per inch is enough for digital needs. Before deciding on a file size, it's important to consider how the image will be used. For example, if the image is only going to be displayed as a thumbnail, there's no reason to waste storage space uploading a high-resolution file to the web. Below, we've outlined how to reduce the size of a JPEG on Windows and Mac.
For Windows

  1. Launch MS Paint: Every Windows user has toyed around with Paint, a fun program that you can use for amateur cartooning and abstract artwork. However, not everyone knows that Paint can also resize images and tweak their resolution. It's so easy to do! First, find the Paint program by clicking Start, 'All Programs', and then 'Accessories'. It doesn't matter if your computer has Windows 95 or Windows 10 — there will be a version of Paint preloaded on your operating system.

  2. Find the Resize Option: To resize an image, select the 'Home' tab and look for the 'Image' heading. There will be a 'Resize' option. When you click on it, a new dialog box will appear with more advanced settings. Before adjusting the size or pixel count, it's important to check the 'Maintain Aspect Ratio' box to keep the image's dimensions intact.

  3. Tweak the Resolution: Besides adjusting the picture's size by a specific percentage, you can also change the resolution. Just click 'Pixels' and decide how many pixels per inch you'd like for the smaller JPEG.

  4. Save a New Version: If you're happy with your new size settings, select 'Save As' from the main menu. We recommend saving a new version of the image, in case you need to use the original file at some point.


For Mac

  1. Launch Preview: Every Mac with OS X has a version of Preview pre-installed on it. The handy program allows you to view and edit image files, so it's perfect for resizing a JPEG. First, open the image in Preview — either by launching Preview in the Applications folder, or control + clicking the image and choosing 'Open With'.

  2. Adjust the Size: Any adjustments to your JPEG can be found under the Tools section of the menu bar. Choose 'Adjust Size' to open a new dialog box called Image Dimensions. This allows you to change the width/height, resolution, and other measurements. For the average user, we recommend changing the measurement to 'percent' and then choosing a number that fits within your target size. When you change this value, the 'Resulting Size' section will tell you exactly how big your new file will be.

  3. Save a New Version: After clicking 'OK', you'll be able to see how the image looks with its new sizing. Fear not — you can undo the changes if it doesn't look right. Just click Command + Z to undo. However, if you're pleased with the results, select File and then 'Save As' to create a new version of your JPEG. Give it a new name, like '[Image] Small' or '[Image] Web Version' and click 'Save'.

In case you need shortcut in resizing your photos and images, Shutterstock has created a free image resizer. Resize your images in these 3 simple steps: upload the image, pick the right size, and download it.

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