The single image options dialog is the main dialog in PhotoGIF‚Ñ¢. It allows you to preview your image, set interlacing, transparency and gives you the option to show additional dialogs for creating multiple image GIF animation files.
 
- The preview
The preview allows you to see the effects of color reduction if saving from RGB mode, the effects of transparency settings and an editing window for the advanced transparency tools. The default position of the preview area is the top, left portion of the image. The horizontal and vertical scroll bars can be used to change the preview area to any portion of the image being saved.
 
- The transparency tools
To the left of the horizontal scroll bar are the transparency tools. They are the brush tool, the dropper tool, and the edge tool, respectively.
 
The brush tool is for removing transparency artifacts that are away from the edges of yourtransparency such as speckles in the transparent area.
 
The dropper tool is used to select the transparent color when using the color transparency method. The dropper can be used to pick a color from the image visible in the preview or from the image palette. Only one transparent color can be selected at a time with the dropper tool.
 
The edge tool can be used to easily and quickly remove unwanted halo effects from the edges of your transparency caused by antialiasing. The edge tool works much like a brush except that absolute precision is not required. The position of the edge tool is only used by PhotoGIF‚Ñ¢ as a starting point to determine the location of the intended edge of the transparency in your image and the length of the edge that has the unwanted halo effect. The operations performed to remove the halo effect after the affected edge has been located with the edge tool are automatic. One pass with the edge tool is generally all that is required to achieve perfect transparency edges.
 
NOTE: The brush and edge tools operate on a transparency mask maintained internally by PhotoGIF™ and do not actually change the image data in the preview or the original image data maintained by Photoshop. If you switch between transparency methods after using the brush or edge tools to correct transparency the changes will be lost. Also, note that changes made in the preview using the brush or edge tools will not change the original open image and those changes will be reverted if you ‘Save’ the open image again. You should close the image, and reopen it to make permanent the changes made using the brush or edge tools.
- The transparency method
Beneath the preview is the ‘Transparency method’ group box. Using PhotoGIF™there are three possible transparency methods, ‘Alpha’, ‘Color’, and ‘None’ that are set with the radio buttons in the ‘Transparency method’ group box.
When the ‘Alpha’ radio button is selected, PhotoGIF™ will use a saved alpha channel as a transparency mask. This may be any alpha channel in the working document, and when the ‘Alpha’ radio button is selected, a popup menu will appear to the left of the ‘Alpha’ radio button for you to select an alpha channel. Note that if there are no alpha channels present, the ‘Alpha’ radio button will be disabled.
When the ‘Color' radio button is selected, PhotoGIF™ will use the color selected with the dropper tool as the transparent color of the GIF file being saved. The decimal and hexadecimal values for the current transparent color will be displayed next to the ‘Color’ radio button and the current transparency color will also be displayed in a large color swatch beneath the values for the selected color.
- The ‘Show multi-image options dialog’ check box
The ‘Show multi-image options dialog’ check box controls whether the dialog for setting options, required for saving multiple image GIF animation files, will be shown.
- The ‘Add to existing GIF file’ check box
The ‘Add to existing GIF file’ check box controls whether additional dialogs, required for appending files together to create multiple image GIF animation files, will be shown. When this option is checked two radio buttons, ‘Create local palette’ and ‘Factor into global palette’, will become active. These control how the palette for the image being saved will be handled, when it is merged with the existing file. ‘Create local palette’ causes a local palette to be used for the image being saved. ‘Factor into global palette’ performs super palette factoring, thus creating a new global palette the multiple image GIF file being created or added, that best represents all the images within the multiple image file.
- The image size read out
The image size readout is the top text line above the palette and is simply a display of the dimensions of the image being saved as pixels-wide by pixels-high.
- The bit-depth read out
The bit-depth readout is the text line directly above the palette. The bit-depth read out displays the lowest depth in bits at which the image can be saved and the number of used colors in the image, which may be fewer than the number of colors contained in the displayed palette.
- The palette
The image’s palette is always displayed. PhotoGIF™ will not change the ordering of colors in the palette, nor remove colors from the palette when the image is saved. This ensures the integrity of palette indexes for multiple image GIF animation applications and when application dependent palettes, such as the Netscape palette, are used.
- The ‘Optimize palette usage’ check box
‘Optimize palette usage’ is a lossy option that further reduces the number of colors used in the image to compensate for palette redundancy and to improve compressibility. The number of colors removed from the image will vary and is automatically determined, based on the values of the colors in the image’s palette. This option does change the appearance of the image being saved and, at times, can cause noticeable loss in image quality, particularly if there are large, smoothly changing gradients in the image. ‘Optimize palette usage’ does allow a very significant saving in file size, but it should be used with caution. It is not recommended to save an image multiple times with the ‘Optimize palette usage’. Note that if ‘Palette optimization’ is used, PhotoGIF™ immediately defaults to no ‘Palette optimization’ for subsequent ‘Save’ operations.
 
- The ‘Interlace’ check box
To the right beneath the palette is the ‘Interlace’ check box. Interlacing allows for the incremental display of GIF images as they download and gives the effect of faster downloading of your image. Note that it is not advisable to save images that are part of multiple image GIF animation files with interlacing.
- The ‘Browser background color’ RGB sliders
The group box titled ‘Browser background color’ contains a set of RGB sliders for setting the color that will be used as your web page background color. Note that this is not the same background color as the background color of your GIF file which can be set in the multiple image options dialog.
 
The browser background color is to allow accurate preview of how your image will look as a transparent GIF and also has effect on how the edge tool operates. You should accurately set the browser background color to the color you intend to use on the page that will contain the image being saved or the results of setting the image's transparency may be different than those you expect.
Each of the sliders in the ‘Browser background color’ group box has a corresponding text edit item that a decimal value can be directly entered in. Note that the sliders themselves are limited to even numerical values and odd numbers must be entered as text. The hexadecimal value of each color component is also displayed.
Appending get file dialog
If you check ‘Append to existing file’ in the single image options dialog, the next dialog shown is the appending get file dialog. This dialog is a standard get file dialog that will allow you to select an image to combine with the image being saved. Note that the file selected in the appending get file dialog is left unmodified, as the images are combined into the file being saved.
 
Appending insertion picker
The appending insertion picker dialog allows you to specify where to put the image you are saving into the multiple image file, being created or modified. It is shown after the appending get file dialog.
The appending insertion picker dialog allows you to preview the images in the file. The sequential number of the currently selected image within the multiple image GIF file is also displayed in the title of the group box surrounding the preview. The check box titled ‘Show’ at the bottom, left of the preview group box, controls the visibility of the image preview. The spinner control to the right of the ‘Show’ checkbox steps forward and backward through the images contained in the multiple image GIF animation file. The edit text box next to the spinner control allows you to enter the number of the image directly.
 
There are three choices for the insertion point of the image being saved. ‘After all images’ inserts the image being saved into the multiple image GIF animation file after all images currently in the file. ‘Before all images’ inserts the image being saved into the multiple image GIF animation file before all images currently in the file. ‘After selected image’ inserts the image being saved after the image currently selected in the preview.
