Usually, many people want to enlarge the picture without losing quality, but it so happens that they simply do not crawl into the mailbox (there is a limitation) or do not climb onto a USB flash drive. In this case, their dpi (from the English "dots per inch", literally "the number of dots per inch" or the resolution of the picture) must be reduced.
Necessary
Computer with Adobe Photoshop installed
Instructions
Step 1
Open the Adobe Photoshop program. In the "Fail" menu, select the "Open" function. In the "Folder" select a specific location (directory, if in the root of the directory), or a folder (if the desired image is located separately from everything).
Step 2
Then, in the field displaying the contents of the folder, select the desired image (highlighted in blue).
Step 3
If you took an image with a camera, then, most likely, the computer will not "ask" you about anything else, and if from some other sources, it will probably throw out the "Missing Profile" window, where it will warn you that this color profile is not built-in for the program. You can choose any of the three suggested options (the last one by default: "Assign profile", with a checkmark under the "and then convert document to working RGB" function) and press the "OK" button.
Step 4
Your image that you want to shrink has opened. Now in the menu "Image" (image) select the sub-item "Image Size" (size of the image) and click on it.
Step 5
In the opened window "Image Size" you need to pay attention to the field "Document Size".
Let's start reducing the image. In the "Width" field (image width), enter a value that is much less than the specified one (for example, 2 times).
Step 6
Note that decreasing the "Width" will automatically decrease the "Height". That is, the program itself (with the "Scale Styles", "Сonstrain Proportions" and "Resampl Image" items set by default) recalculates this value.
Pay attention to the "Pixel Dimension" field. It contains the information we need about how many dpi was in the image and how much it has become. In this example, you can see that the picture has been reduced by half (it was 1, 37M, now 346 Kb).
Step 7
We save the picture in the desired folder under a different name so as not to be confused with the previous one (an image with a good resolution will always come in handy). When saving, select the ".jpg" format - it opens on any computer and click on "Save".
Step 8
In the "JPEG Options" window that opens, set "Qualiti" (image quality), preferably from 9 to 12. The "Progressive" sub-item is usually the default. Click on "OK".
The thumbnail image is in the desired folder, ready for sending over the Internet or recording to electronic media.
