PHOTO TUTORIAL RESIZING IMAGES This tutorial has been compiled for those people who would like to submit photos to the Projected Images category in the NEPG monthly competitions, and who are unsure on how to resize their images. The NEPG competition rules, changed in August 2012, state that: longest size of image to be no more than 2000 pixels long, saved as jpeg no larger than 1Mb, compression no less than 8 in quality. Examples are given below on how to resize images using Photoshop (Elements and CS), Picasa (free Google download) and Canon and Nikon software (usually shipped with the camera). There are many other programmes that can achieve the same. Be aware that there may be some loss of quality in the process of resizing. Automatic resizing by email programmes (such as Outlook) usually results in very small file sizes and significant loss of quality. The same resizing methods can be used for emailing images, as an attachment to an email message. However, usually a smaller file size is required. This can be achieved by using a combination of reducing pixels and reducing quality. Most programmes have predetermined settings for emailing images. Always make sure that you keep the original image in the original size/resolution! A bit of theory: Image Size is related to the number of pixels. Generally, the more pixels, the sharper the image is ( better resolution ); Screens and projectors work with 72 pixels/inch resolution. Having a higher resolution does not improve your image on the screen. JPEG Quality refers to the compression: A higher level of compression (where JPEG omits information) results in lower image quality, and a smaller file size. Use Maximum quality wherever the image size allows. Paul Sauter October 2012 RESIZING IMAGES v3 PS Oct 2012 1
ADOBE PHOTOSHOP CS* AND ELEMENTS Open the image (e.g. jpg, PSD etc) you want to resize; o In CS*: Image>Image size; o In Elements: Image>Resize>Image Size; If not already set, set the resolution to 72 pixels/inch; Make sure the Resample Image is ticked and set to Bicubic and that the other tick boxes are ticked; Set the Width to 2000 pixels (for a Landscape format) (or Height for a Portrait format); OK; The small, resized image will appear on your screen; Rename the file by File>Save As, and give the file a new name (in JPEG format), then: Save; On the next menu (JPEG Options), move the slider to large file, so that the Quality is 12 and Maximum, and check the size of the image on the right-hand side. For NEPG purposes, the size has to be below 1Mb. If the size is still too large, there are two options: move the slider a couple of steps to the left towards small file and reduce the Quality; or go back to the previous screen and reduce the pixels; RESIZING IMAGES v3 PS Oct 2012 2
As an example: a 7Mb jpg from my 18 megapixel camera gets reduced to 2Mb with a Quality of 12; to 1.3Mb with a Quality 11; and to 930Kb (=0.93 Mb) with a Quality 10. In the old system, with a pixel size of 1024, and a Quality of 12, the same image is 721Kb. At a cursory glance, I can t see any difference between the 12, 11 and 10 Quality settings, but I m definitely losing some sharpness and spark with the 1024 pixel setting. So, in general, losing a bit of Quality is preferable over losing pixels. Press OK, and this will create the new resized file. If you use sharpening on your image, e.g. Unsharp Mask, do this only after you have completed the resizing, and examine the image for any anomalies on screen at 100% magnification. You may find that, if you have converted from RAW, and have been editing in PSD in Photoshop, the reduction to 72 pixels/inch resolution already brings the pixel dimensions to below 2000. Check if the file size is ok with Quality 12, otherwise bring the Quality back a bit. RESIZING IMAGES v3 PS Oct 2012 3
PICASA Highlight the jpg image you want to resize; File>Export Picture to Folder; In the next window, specify the exported folder, and the Resize to 2000 pixels; Select Automatic for Image Quality; Export; RESIZING IMAGES v3 PS Oct 2012 4
This will create the resized photo, with a suffix like -1, if it has been created in the same folder, or with the same filename if created in a new folder. In that case, rename to a new filename, using File>Rename. Check if the file size is correct. It can be changed by running the export again with a different Image Quality setting. Try to get as close as possible to the maximum 1Mb. RESIZING IMAGES v3 PS Oct 2012 5
CANON ZOOMBROWSER EX Highlight the jpg image you want to resize; Right-click Export> Export Still Images, or File>Export>Export Still Images; Select Resize and 2000 pixels for the Long Side (for Landscape); Change Image Format, choose jpg and Highest Quality; Check the new Size: if above 1Mb, bring the Quality back a bit. Select the folder; click Finish; The programme will create a new image with the same name plus suffix _1. NIKON VIEWNX Highlight the jpg image you want to resize; Output>Convert Files; Select Excellent Quality, and Change the image size to 2000 pixels (for Landscape); Choose a folder to put the new image in; Convert; The programme will create a new image with the same name plus suffix _01. If the image is still too large, try changing the Quality. RESIZING IMAGES v3 PS Oct 2012 6